1. Find the maximum and minimum values of f(x) on the given interval.
(a) f(x)=(square root of x)-4x, 0 is less than or equal to x is less than or equal to 4.
(b) f(x)=sinx+cosx, 0 is less than or equal to x is less than or equal to pi/2.
(c) f(x)=xe^-x, 0 is less than or equal to x is less than or equal to 2.
(d) f(x)=lnx/x, 1 is less than or equal to x is less than or equal to 3.
2. Find the minimum value of f(x) for x is greater than 0.
(a) f(x)=(x^-2)-(4x^-1)
(b) f(x)=x^x