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Drizzle Hinata
11/29/2025
Trigonometry
Basic Trigonometric Identities
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Nov 29, 2025
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Trigonometric identities are powerful mathematical relationships that help solve complex... Show more
Ever wondered how mathematicians solve complex angle problems? It all starts with these basic relationships. The most fundamental identities define how trig functions relate to each other.
The basic definitions connect all six trig functions: sine, cosine, tangent, cotangent, secant, and cosecant. For example, tangent equals sine divided by cosine, and secant is the reciprocal of cosine.
The Pythagorean identity, sin²x + cos²x = 1, forms the backbone of trigonometry. This relationship leads to two other important identities: 1 + tan²x = sec²x and cot²x + 1 = csc²x.
Double angle formulas like sin(2x) = 2sinx·cosx and cos(2x) = cos²x - sin²x let you find values of twice an angle when you know the original angle. These are especially useful in calculus and physics problems.
💡 Pro Tip: When solving trig problems, remember that sine is an odd function while cosine is an even function . This can dramatically simplify your calculations!
The unit circle is your secret weapon for understanding how trigonometric functions behave across different quadrants. When you move around the circle, the trig values follow predictable patterns.
Angle relationships like cos = -cos(x) and sin = -sin(x) help you calculate values without memorizing everything. Notice how adding π (180°) to an angle changes the signs in specific ways.
The complementary angle relationship is particularly useful: sin = cos(x) and cos = sin(x). This explains why sine and cosine are essentially the same function, just shifted by 90°.
When working with angles, you can simplify your work by recognizing patterns. For example, any angle plus 2π (a full 360° rotation) returns to the same trig values: sin = sin(x) and cos = cos(x).
💡 Remember: You can derive many of these identities visually by drawing the unit circle and tracking what happens to coordinates as you move around it!
Double angle formulas can transform difficult problems into simpler ones. For instance, sin(2x) = 2sin(x)cos(x) allows you to convert products into sums, which are often easier to integrate.
The half-angle formulas like sin = ±√ are powerful when you need to find values for half of a known angle. The ± sign depends on which quadrant the angle falls in.
Sum and difference identities help you break down complex angles into simpler components. Using sin = sinA·cosB + cosA·sinB lets you calculate sine values of combined angles when you know the individual values.
These formulas are especially useful in calculus when integrating products of trigonometric functions. They also appear in physics when analyzing wave interference and in engineering when working with periodic signals.
💡 Application Insight: In computer graphics and game development, these identities help calculate rotations of objects in 3D space efficiently!
The Laws of Sines and Cosines are your go-to tools for solving triangles when you don't have a right angle. These formulas connect side lengths to angles and work for any triangle shape.
When analyzing projectile motion in physics, parametric equations use trigonometric functions to track position. The formula X = (v cos θ)t shows how horizontal distance depends on the launch angle.
Converting between rectangular and polar coordinates becomes simple with trig: r = √ and θ = tan⁻¹. This transformation is crucial in calculus and engineering applications.
The angle between vectors formula uses the dot product and trigonometric functions, making it essential for physics problems involving forces and motion. Similarly, the quadratic formula and sine/cosine graphing equations demonstrate how trig functions appear throughout mathematics.
💡 Test Tip: When graphing sine or cosine functions like y = a·sin+d, the coefficient 'a' affects the height (amplitude), 'b' affects how squeezed or stretched the graph is , 'c' shifts it horizontally, and 'd' shifts it vertically.
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
App Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Trigonometric identities are powerful mathematical relationships that help solve complex problems involving angles and triangles. These formulas connect different trigonometric functions and allow you to transform expressions in ways that make calculations easier.
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered how mathematicians solve complex angle problems? It all starts with these basic relationships. The most fundamental identities define how trig functions relate to each other.
The basic definitions connect all six trig functions: sine, cosine, tangent, cotangent, secant, and cosecant. For example, tangent equals sine divided by cosine, and secant is the reciprocal of cosine.
The Pythagorean identity, sin²x + cos²x = 1, forms the backbone of trigonometry. This relationship leads to two other important identities: 1 + tan²x = sec²x and cot²x + 1 = csc²x.
Double angle formulas like sin(2x) = 2sinx·cosx and cos(2x) = cos²x - sin²x let you find values of twice an angle when you know the original angle. These are especially useful in calculus and physics problems.
💡 Pro Tip: When solving trig problems, remember that sine is an odd function while cosine is an even function . This can dramatically simplify your calculations!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The unit circle is your secret weapon for understanding how trigonometric functions behave across different quadrants. When you move around the circle, the trig values follow predictable patterns.
Angle relationships like cos = -cos(x) and sin = -sin(x) help you calculate values without memorizing everything. Notice how adding π (180°) to an angle changes the signs in specific ways.
The complementary angle relationship is particularly useful: sin = cos(x) and cos = sin(x). This explains why sine and cosine are essentially the same function, just shifted by 90°.
When working with angles, you can simplify your work by recognizing patterns. For example, any angle plus 2π (a full 360° rotation) returns to the same trig values: sin = sin(x) and cos = cos(x).
💡 Remember: You can derive many of these identities visually by drawing the unit circle and tracking what happens to coordinates as you move around it!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Double angle formulas can transform difficult problems into simpler ones. For instance, sin(2x) = 2sin(x)cos(x) allows you to convert products into sums, which are often easier to integrate.
The half-angle formulas like sin = ±√ are powerful when you need to find values for half of a known angle. The ± sign depends on which quadrant the angle falls in.
Sum and difference identities help you break down complex angles into simpler components. Using sin = sinA·cosB + cosA·sinB lets you calculate sine values of combined angles when you know the individual values.
These formulas are especially useful in calculus when integrating products of trigonometric functions. They also appear in physics when analyzing wave interference and in engineering when working with periodic signals.
💡 Application Insight: In computer graphics and game development, these identities help calculate rotations of objects in 3D space efficiently!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The Laws of Sines and Cosines are your go-to tools for solving triangles when you don't have a right angle. These formulas connect side lengths to angles and work for any triangle shape.
When analyzing projectile motion in physics, parametric equations use trigonometric functions to track position. The formula X = (v cos θ)t shows how horizontal distance depends on the launch angle.
Converting between rectangular and polar coordinates becomes simple with trig: r = √ and θ = tan⁻¹. This transformation is crucial in calculus and engineering applications.
The angle between vectors formula uses the dot product and trigonometric functions, making it essential for physics problems involving forces and motion. Similarly, the quadratic formula and sine/cosine graphing equations demonstrate how trig functions appear throughout mathematics.
💡 Test Tip: When graphing sine or cosine functions like y = a·sin+d, the coefficient 'a' affects the height (amplitude), 'b' affects how squeezed or stretched the graph is , 'c' shifts it horizontally, and 'd' shifts it vertically.
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
