The derivative of sine squared is the sine of 2x, expressed as d/dx (sin2(x)) = sin(2x). The derivative function describes the slope of a line at a given point in a function.

The derivative of sine squared can be determined by using the chain rule. Under the chain rule, the equation becomes two times the sine of x times the derivative of the sine of x. The derivative of the sine of x is the cosine of x, resulting in the formula 2sin(x)cos(x). The formula 2sin(x)cos(x) can be simplified down to the sine of two times x, expressed as sin(2x).