It is sine of x squared. If I, no matter what was inside of these orange parentheses, I would put it inside of the orange parentheses and these orange brackets right over here. We learned that in the chain rule. So let's see, we know this is just a matter, the first part of the expression is just a matter of algebraic simplification. But the second part, we need to now take the derivative of sine of x squared. Well now, we would want to use the chain rule again. So I'm gonna take the derivative, it's sine of something.