PreCalculuscheck answers
posted by Lucy on .
Express 52i in polar form. Express your answer in radians to the nearest hundreth.
r=sqrt5^2+2i^2 which equals sqrt21.Arctan of 2/5+pi equals 18.7
Polar form=sqrt21 cis 18.7
Is this correct??

not quite
if x+iy = r e^iT = r (cos T i sin T)
then
r = sqrt (x^2+y^2)
not sqrt [x^2 + (iy)^2]
so r = sqrt (29), not 21