Question

What is the minimum value of the function y = x2 + 16x + 61

Answer 1

1. when a function is at a minima or maxima,
\[{dy\over dx}=0\]
find "x"
2. now, to make sure it is a minima,
find the second derivative \(d^2y\over dx^2\)
put the value of "x" from step 1. if the answer is positive, you have a minima
if negative, maxima