#### Hckyplayer8

##### Junior Member

- Joined
- Jun 9, 2019

- Messages
- 248

b) Determine the intervals where f is increasing and decreasing

c) Classify as a local max, min or neither

d) Determine the intervals where f is concave up or down

e) Determine points of inflection

a) f ' (x) = 1 - sin x

Setting that to zero and quick double check on the unit circle shows sin x = 0 at x = pi over 2

This is probably obvious to the math savvy, but is there a technique for selecting the x's to test f ' at for these unit circle questions? For example, sin pi/2 = 90 degrees. But Calculus likes to take those very, very, very small intervals and the next angle in the unit circle is +/- 30 degrees...