2x³y³/4y² i need there are no choices

What basic trigonometric identity would you use to verify that sin x cos x tan x =1-cos^(2)x?

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

What is the value of f(x) = 2.2 for f(-2)?