i understand we need to use the chain method here but isnt p

i understand we need to use the chain method here. but isnt product rule also in effect?

can someone tell me in steps how to solve this?

id think youd do

sec^2 and then use the product rule for dir. of cos times dir of 5?

sec^2 ( cos X 5 ) + ( -sin X 5x) ?

Solution

dy/dx=sec²(cos5x)[d(cos5x)/dx]

=[sec²(cos5x)](-sin5x)[d(5x)/dx]

=[sec²(cos5x)](-sin5x)(5)

=-5(sin5x)(sec²(cos5x))