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November 25, 2015
Posted by **Lucy** on Saturday, September 13, 2008 at 4:09pm.

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??

- Pre-Calculus-check answers -
**Damon**, Saturday, September 13, 2008 at 6:04pmnot 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