2nd derivative test is easy to do ...
to see if its a max/min
like if I get 2cosx = 0 at pi/2 (so pi/2 would be my critical point)
do I plug that in back to the original equation? What do I do. Thanks
To test if a point is a maximum, the function's second derivative will be negative at that point.
To test if a point is a minimum, the function's second derivative will be positive at that point.
If the second derivative happens to be 0 at that point, you can't state anything.