Question

define maxima and minima of a function

Answer 1

Any function can be illustrated in the form of a wave. The maximum height reached by the wave is called the maxima while the lowest point the wave reaches is the minima.
to find the maxima and minima differentaie the function once, equate it to zero, find the critical  points. Substitute the points in the equation, you'll get two values. Substitute the given limits also. The highest of them all is the maximum.