Question

Вычислить производные функций в точке

Answer 1

$a) f(x) = \arccos x\\f'(x) = -\frac{1}{\sqrt{1-x^2}}\\f'(0) = -\frac{1}{\sqrt{1-0^2}} = -\frac{1}{\sqrt{1-0}} = -\frac{1}{\sqrt{1}} = -\frac{1}{1} = -1\\\\b) f(x)=x^3\cos x\\f'(x) = (x^3)' \cos x + x^3 (-\sin x) = 3x^2 \cos x -x^3\sin x\\f'(0) = 3\cdot0^2 \cos 0 -0^3\sin 0 = 3\cdot 0 \cos 0 - 0\sin 0= 0$