Differentiate the equation

Question

Differentiate y = sin²x - cos²x.

Question 5 options:

1)	2sin(x) - 2cos(x)
2)	2sin(x) + 2cos(x)
3)	4sin(x)cos(x)
4)	0

Answer 1

y = sin²x - cos²x

y' = d/dx(sin²x - cos²x) = 2·Sin x·Cos x - 2·Cos x · (-Sin x) = 2·Sin x·Cos x + 2·Cos x · Sin x = 4·Sin x·Cos x