The force $\displaystyle F$ (in pounds) on a person's back when he or she bends over at angle (in degrees) is modeled by

$\displaystyle F = \frac {0.6W\sin {(\Theta + 90)}}{\sin{12}}$

where $\displaystyle W$ is the person's weight (in pounds).

a) Simplify the model.

Would it just be $\displaystyle F = \frac {0.6W\cos {\Theta}}{\sin{12}}$ since $\displaystyle \sin{(\Theta +90)} = \cos{\Theta}$ ?

b) Use a graphing utility to graph the model, where $\displaystyle W = 185$ and $\displaystyle 0 < \theta < 90$.

This is done.

c) At what angle is the force a maximum? At what angle is the force a minimum?

The angle is at a maximum at 0 and 360 degrees and minumum at 180 degrees. Does that seem right? Because at 180 degrees$\displaystyle F$is negative.

I have also attached a picture of the original problem.