Chapter 13.1, Problem 1CP

Plot the function $y=f(x)$

, and find a length-one starting interval on which f is unimodal around each relative minimum. Then apply Golden Section Search to locate each of the function’s relative minima to within five correct digits.

$\begin{array}{l}\text{a}\text{. }f(x)=2x^4+3x^2-4x+5\\ \text{b}\text{. }f(x)=3x^4+4x^2-12x^2+5\\ \text{c}\text{. }f(x)=x^6+3x^4-2x^3+x^2-x-7\\ \text{d}\text{. }f(x)=x^6+3x^4-12x^3+x^2-x-7\end{array}$