Question

Calculate the derivative indicated.
d2ydx2∣∣∣x=8 where y=91x3+7x2


Answer:

Answer 1

$y'=91\cdot3x^2+7\cdot2x=273x^2+14x$

$\frac{d^2y}{dx^2}=y''=273\cdot2x+14=546x+14$

$\frac{d^2y}{dx^2}|_{x=8}=546\cdot8+14=4382$

Answer: 4382.