Question

f(x)= cos(3x). Find f"(pie/3)​

Answer 1

F(x)= cos(3x)

F'(X) = -3sin(3x)

F''(X) = -9cos(3x)

Pie/3 = 180/3 = 60°

F''(60°) = -9 cos(180)

= -9 (-1) = 9