Trigonometry Question 5

Question

simplify using the correct double angle formula. cos(2x)+2sin^2 (x)

Answer 1

Hi Katie

You can look up the Double Angle Identities in your text or online for the following:

cos(2x) = 1 - 2sin²x

Substitute this in your equation

cos(2x) + 2sin²x

1 - 2sin²x + 2sin²x = 1

Hope this helps

By the way there are several identities for cos(2x) they are

cos (2x) = cos²x - sin²x

cos (2x) = 2cos²x - 1

cos(2x) = 1 - 2sin²x

You can use them to confirm the answer above