Question

find the polar coordinates that correspond to (11,-11)

Answer 1

the radius is equal to the distance from the origin (0,0) to (11,-11)

r = sqrt( (11^2) + (-11^2) )

the angle of rotation is equal to cos^-1(11/r) or sin^-1(-11/r) ; just remember that it is in the forth quadrant. So, sin^-1 is probably more helpful; since it spits an angle at you that is either in Q1 or Q4.

Answer 2

just at a quick glance; r= 11sqrt(2).