Exponential to Polar form help please

jayjay · #1 $Old$ November 11th, 2009, 09:55 AM

guys, I just cant understand this.. the question is :

express e^-4-2j in polar form, the answer to the question is given which is :

e^-4-2j = e^4 cjs(-2) = 0.018 cjs (-114.6 degree) = 0.018 angle -114.6

my question is I don't know how he got -114.6 degree's, the 0.018 is e^4 and I thought that the -114.6 is 0.018(cos(-2) + sin(-2) but i dont get the same answer =S, help please.

regards

BobP · #2 $Old$ November 12th, 2009, 02:37 AM

The minus 2 is minus 2 radians. Just convert it to degrees.

$cjs(-2)$ is an abbreviation for $\cos(-2)+j\sin(-2).$