Question

3. Вычислите f' (π/4), если f(x)=3cos(x)+4x2−2πx+5;

Answer 1

$f(x)=3cosx+4x^2-2\pi x+5\\\\f'(x)=-3sinx+8x-2\pi\\\\f'(\frac{\pi}{4}=-3sin\frac{\pi}{4}+8\cdot \frac{\pi}{4}-2\pi =-3\cdot \frac{\sqrt2}{2}+2\pi-2\pi =-\frac{3\sqrt2}{2}$