Question

F(x)=cosx. Найдите F'(-3π/4)

Answer 1

$f(x)=cosx \\\\ f'(x)=-sinx \\\\ f'(- \frac{3 \pi }{4} )=-sin(- \frac{3 \pi }{4} )= \frac{ \sqrt{2} }{2}$

Answer 2

F(x)=cosx

F'(x)= -sinx

F'(-3π/4)= -sin(-3π/4)=-(-√2/2)=√2/2