Complex Plane - GRE Subject Test: Math

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Question

Write the complex number in polar form, where polar form expresses the result in terms of a distance from the origin on the complex plane and an angle from the positive -axis, , measured in radians.

Answer

To see what the polar form of the number is, it helps to draw it on a graph, where the horizontal axis is the imaginary part and the vertical axis the real part. This is called the complex plane.

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To find the angle , we can find its supplementary angle and subtract it from radians, so .

Using trigonometric ratios, and .

Then .

To find the distance , we need to find the distance from the origin to the point . Using the Pythagorean Theorem to find the hypotenuse , or .

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