Question

The point whose polar coordinates are $(5,-{30}^o)$ is the same as the point whose polar coordinates are

• A. $(5,{30}^o)$
• B. $(-5,{150}^o)$
• C. $(5,-{150}^o)$
• D. $(-5,-{30}^o)$
• E. $(5,{150}^o)$

Answer 1

Answer: (B)

$(-5,{150}^o)$

Basically Polar coordinates are (r, angle).

here we have r=5, and angle= -30 degree

When we rotate polar coordinates in anticlockwise direction. Then the polar coordinates will be (-r, angle+pi).

Thus polar coordinates will be (-5, -30+180 degree)

i.e, (-5, 150 degree)