Brilliant

Home Courses Today

Excel in math and science.

Log in with Facebook Log in with Google Log in with email

Join using Facebook Join using Google Join using email

Forgot password? New user? Sign up

Existing user? Log in

Your answer seems reasonable. Find out if you're right!

Sign up to access problem solutions.

That seems reasonable. Find out if you're right!

Sign up to save your progress!

Log in with Facebook Log in with Google Log in with email

Join using Facebook Join using Google Join using email

Forgot password? New user? Sign up

Existing user? Log in

Proving Trigonometric Identities

Concept Quizzes

Proving Trigonometric Identities Warmup
Proving Trigonometric Identities
Advanced Proving Identities using Pythagorean
Proving Sum and Difference Trigonometric Identities

Challenge Quizzes

Proving Trigonometric Identities: Level 4 Challenges

Proving Sum and Difference Trigonometric Identities

Which of the following is equal to $\sin(x+y)\sin(x-y)?$

\sin2x

\sin(x^2-y^2)

\cos^2x-\cos^2y

\cos^2y-\cos^2x

Show explanation

View wiki

by Brilliant Staff

Which of the following is equal to $\displaystyle \frac{\sin x + \sin 3x}{\cos x - \cos 3x}?$

\cot 2x

\cot x

\tan 2x

\tan x

Show explanation

by Brilliant Staff

If $x,y,z$ are the internal angles of a triangle, which of the following is equal to the sum $\sin x+\sin y+\sin z?$

0

\sin x\sin y\sin z

4\cos\frac{x}{2}\cos\frac{y}{2}\cos\frac{z}{2}

\frac{1}{4}\tan 2x\tan 2y\tan 2z

Show explanation

View wiki

by Brilliant Staff

Evaluate $\cos^2\theta+\cos^2\left(\theta+\frac{2}{3}\pi\right)+\cos^2\left(\theta-\frac{2}{3}\pi\right).$

0

\frac{1}{2}

1

\frac{3}{2}

Show explanation

View wiki

by Brilliant Staff

If $x,y,z$ are the internal angles of a triangle, which of the following is equal to the sum $\cos^2x+\cos^2y+\cos^2z?$

1-2\sin x\sin y\sin z

1-2\cos x\cos y\cos z

\tan 2x\tan 2y\tan 2z

-\cot\frac{x}{2}\cot\frac{y}{2}\cot\frac{z}{2}

Show explanation

View wiki

by Brilliant Staff

×

Problem Loading...

Note Loading...

Set Loading...