What is the distance between the following polar coordinates?: (4,π),(5,π)

2 Answers
Dec 26, 2015

1

Explanation:

The distance formula for polar coordinates is

d=r21+r222r1r2cos(θ1θ2)
Where d is the distance between the two points, r1, and θ1 are the polar coordinates of one point and r2 and θ2 are the polar coordinates of another point.
Let (r1,θ1) represent (4,π) and (r2,θ2) represent (5,π).
d=42+52245cos(ππ)
d=16+2540cos(0)
d=41401=4140=1=1
d=1
Hence the distance between the given points is 1.

Dec 29, 2015

1

Explanation:

(this is an attempt to restore my original answer)

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Using common insight rather than applying the Pythagorean Theorem and cos conversions:

The distance between any two polar coordinates with the same angle is the difference in their radii.