Sore kaka,... mohon bantuanya yah no.8 dan 9 beserta caranya. Terimakasih. No spam please.

8) f(x) = 1/(2x^2) = (1/2)x^-2
f'(x) = (1/2) . -2 x^(-2 - 1)
f'(x) = -1 x^-3 => f'(1) = -1 (1)^-3 = -1 (1) = -1

9) f''(x) = -1 . -3 x^(-3 - 1) = 3x^-4
f''(1) = 3(1)^-4 = 3(1) = 3