Question

Convert the polar representation of this complex number into its rectangular form:
z=7(cos(pi/2)+ i sin(pi/2))
A. (0,-7)
B. (0,7)
C. (7sqrt(3), 0)
D. (-7,0)

Answer 1

B. (0,7)

Answer 2

why is that correct?

Answer 3

@hartnn

Answer 4

as cos(pi/2) =0 and sin(pi/2)=1
for (x,y) correspond to some form of a+ib

Answer 5

@hartnn

Answer 6

pi/2 is the standard angle, you must remember its cos and sin values.
then its just the matter of substitution.

Answer 7

the i is messing with me here... lil help?

Answer 8

in co-ordinates a+bi can be represented as (a,b)
so, 0+7i will be represented as (0,7).

Answer 9

so... that was right?

Answer 10

yup.