[填空题]
Consider the function f(X:m gdu,ap)u.*yeo/m)xu6w 1bzcr 9jf)=a9 xil3o:ba8 osur.n* 2x$^4$ + 1.
1.Find f′(x)=ax$^3$, a= .
2.Find the gradient of the graph of f at x=−1.
f′(-1)=- .
3.Find the x-coordinate of the point at which the normal to the graph of f has a gradient of −8.
x=$\frac{a}{b}$, a= , b= .
