Question 4 • Math 4
Using the standard angles, cos(π/2) = 0 and sin(π/2) = 1, so w = 4i. Also, cos(3π/2) = 0 and sin(3π/2) = −1, so z = −3i. Therefore, w + z = i, which has modulus 1 and angle π/2. Its polar form is cos(π/2) + i sin(π/2), the choice that gives the correct result.
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