Engineering Board Exam Reviewer · Polar Coordinates · medium

Convert the polar equation r=4 to rectangular form.

1. x2 + y2 - 4 y = 0
2. x2 + y2 - 16 = 0
3. x2 - 4 x + y2 = 0
4. x2 - 2 x + y2 = 0

Answer

C. x2 - 4 x + y2 = 0

Solution

Multiply by r: r2=4r x2+y2=4x, i.e. x2+y2-4x=0 (a circle with center (2,0)).

More Polar Coordinates questions

1. Convert the rectangular point (-3,3) to polar coordinates (r, ) with r>0 and 0°≤ <360°.
2. Convert the polar point (4,60°) to rectangular coordinates.
3. Find the point of intersection, with 0°< <90°, of the curves r=2 and r=4 .
4. Express the line x=4 in polar form.
5. Find the eccentricity of the conic r=6/2+ .
6. Identify the conic r=3/1+ .
7. Find the distance between the polar points (3,30°) and (5,90°).

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