Double Angle Formulas

Question 0

What is { cos(2x) } equal to ?

3 answers required ..

Answer 0

1 ) cos(2x) = cos^2 x - sin^2 x

2) cos(2x) = 1 - 2 sin^2 x
3) cos(2x) = 2 cos^2 x - 1

Question 1

What is { sin(2x) } equal to ?

Answer 1

Sin(2x) = 2 sinx cosx

Question 2

Sin6x = ?

Answer 2

Sin(6x) = sin2(3x)

= 2 sin(3x) cos(3x)

Question 3

cos(8x) = ?

Answer 3

cos(8x)

= cos^2 (4x) _ sin^2 (4x)