**2.** Using polar coordinates, evaluate

**3.** Use Lagrange multipliers to prove that the triangle with maximal area that has a given
perimeter *P* is equilateral.[**HINT:** Use Heron's formula for the area :
where
and *x*,*y* and *z* are the lengths of the sides].

**4.** Let *S* be the surface

Find the point of

**5.** Find the tangential and normal components of the acceleration of
.
Compute the curvature of the trajectory at time *t*=0.