Question #c1e7d

1 Answer
Dec 13, 2016

Please see the explanation

Explanation:

Verify: #(sin(theta) + cos(theta))^2 = 1 + 2sin(theta)cos(theta)#

I will only make changes to the left side.

Expand the square:

#sin^2(theta) + 2sin(theta)cos(theta) + cos^2(theta) = 1 + 2sin(theta)cos(theta)#

Move the swap the second and third terms:

#sin^2(theta) + cos^2(theta) + 2sin(theta)cos(theta) = 1 + 2sin(theta)cos(theta)#

Use the identity #1 = sin^2(theta) + cos^2(theta)#:

#1 + 2sin(theta)cos(theta) = 1 + 2sin(theta)cos(theta)#

Verified.