Which complex number would be graphed at the point (-2,2)?

a) 2(cos7pi/4+i sin 7pi/4)
b) -2(cos135+i sin 135)
c) 2sqrt(2)(cos3pi/4 + i sin 3pi/4)
d) 2sqrt(2)(cos 225 + i sin 225)

Question

Which complex number would be graphed at the point (-2,2)?

a) 2(cos7pi/4+i sin 7pi/4)
b) -2(cos135+i sin 135)
c) 2sqrt(2)(cos3pi/4 + i sin 3pi/4)
d) 2sqrt(2)(cos 225 + i sin 225)

anonymous · Answer

attachment

kropot72 · Answer

$$r=\sqrt{2^{2}+2^{2}}=\sqrt{8}=2\sqrt{2}$$
The angle is in the second quadrant. So that leaves one choice.

anonymous · Answer

Which answer is that?

kropot72 · Answer

Which one of C and D has the angle in the second quadrant?

anonymous · Answer

Is it C?

anonymous · Answer

THANK YOU! IT WAS! Thank you for narrowing it down for me, you're a life saver.

kropot72 · Answer

The correct choice is C. Choice D has the angle in the third quadrant.

kropot72 · Answer

You're welcome :)