Determine two pairs of polar coordinates for the point (5, -5) with 0° ≤ θ < 360°?

Help me with this problem pleaseeee.

The answer choices given are:

1) (5 sqrt2 , 315°), (-5 sqrt2 , 135°)

2) (5 sqrt2 , 45°), (-5 sqrt2 , 225°)

3) (5 sqrt2 , 135°), (-5 sqrt2 , 315°)

4) (5 sqrt2 , 225°), (-5 sqrt2, 45°)

2 Answers

  • Since the point lies in the third quadrant

    cos(θ) = x/r where r^2 =x^2+y^2 =5^2(-5)^2 =25+25 = 50 , r = sqrt(50) =5sqrt(2)

    cos(θ) = x/r =5/5sqrt(2) =1/sqrt(2) = cos(135)

    Hence answer is = (5 sqrt2 , 315°), (-5 sqrt2 , 315°)……………….Ans

  • option 1) (5 sqrt2 , 315°), (-5 sqrt2 , 135°) is correct :)>

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