Trigonometric Double Angle Identities Quiz
Which expression is equivalent to 1/1-2sin^2(x)?
1/cos(2x)
What is the error in this derivation?
In step 3, cos^2(x) - 1 - cos^2(x) should be cos^2(x) - 1 + cos^2(x).
Simplify cos(2x)/cos(x)+sin(x)
cos(x)+sin(x)
Which expression is equal to 2sin(pi/10)cos(pi/10)?
sin pi/5
Suppose cos(x)=-1/3 where pi/2<x<pi. What is the value of tan(2x)?
2 sqrt8/7
Which expression is equivalent to cos(4x)?
2(2cos^2(x) - 1)^2 - 1
Which derivation correctly uses the cosine sum identity to prove the cosine double angle identity?
First Table A
Consider the derivation of sin(2x). Where is the error?
Step 3 should read = 2sin(x)cos(x).
Let sin(2x) - sin(x) = 0, where 0 ≤ x < 2π. What are the possible solutions for x?
{0,pi/3,pi,5pi/3}
Let cos(2x) - cos(x) = 0, where 0° ≤ x ≤ 180°. What are the possible values for x?
0° or 120°