# Math Help - After solving a trig function to find critical points, how do you test them...

1. ## After solving a trig function to find critical points, how do you test them...

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

2. ## Re: After solving a trig function to find critical points, how do you test them...

2nd derivative test is easy to do ...

3. ## Re: After solving a trig function to find critical points, how do you test them...

What would I do for that?

4. ## Re: After solving a trig function to find critical points, how do you test them...

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.