Do the highlighted question only in 8 and 9

8: For each function f below, find any local extrema of f by using the second derivative test, if it applies. If the second derivative test does not apply, explain why and then use the first derivative test. (a):f(x)=2(4x+1)3 (b): f(x)=(1x)42 9: Calculate the first derivative of the following functions. (a): f(x)=xx1 (b): f(t)=t+13t25 (c): f(r)=r32(r3r) (d):f()=324+2