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# FP1 modulus-arg form of complex numbers watch

1. how do i express the modulus-arg form as x+iy?

for e.g, 5(cos pi/2 + i sin pi/2)

i know that r is 5 and theta is pi/2 but where do i go from here?

thnx
2. (Original post by borborygmus)
how do i express the modulus-arg form as x+iy?

for e.g, 5(cos pi/2 + i sin pi/2)

i know that r is 5 and theta is pi/2 but where do i go from here?

thnx
Well, expand, and if possible (in this case it is) evaluate the cos and sine.
3. (Original post by borborygmus)
how do i express the modulus-arg form as x+iy?

for e.g, 5(cos pi/2 + i sin pi/2)

i know that r is 5 and theta is pi/2 but where do i go from here?

thnx
Just evaluate the given expression. You know what and are so evaluate them and then multiply the result by five.

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