What interval is f increasing in interval notation? On what interval is f concave up and down in interval notation?
What are the x coordinates of inflection points?

i believe it's a.

i'm not sure on this one, most likely correct.

38.6°

step-by-step explanation:

resultant is 10 pound

smaller force = 8 pound

angle formed = tan⁻¹(

                        =tan⁻¹(

                          =tan⁻¹(0.8)

                        =38.6°