Question 150317: Please help me answer the following:
(-5,12) are the coordinates of a point in rectangular form. Find this point in polar form (r,A), with A expressed in radians.
The answer choices include:
1. (13,112.6)
2. (13,1.97)
3. (10.9,1.97)
4. (10.9,112.6)
Thanks, Tami
Answer by Edwin McCravy(20060) (Show Source):
You can put this solution on YOUR website! Please help me answer the following:
(-5,12) are the coordinates of a point in rectangular form.
Find this point in polar form (r,A), with A expressed in radians.
The answer choices include:
1. (13,112.6)
2. (13,1.97)
3. (10.9,1.97)
4. (10.9,112.6)
Thanks, Tami
Plot the point:
Draw a perpendicular from the point down to the x-axis,
label it , the y-coordinate.
Label the x-coordinate .
Draw a radius vector (r) from the point to the origin.
Indicate the angle A with a curved line.
Now we calculate r using the Pythagorean theorem:
And we calculate angle A by the trig equation
We find the reference angle using the inverse tangent:

However, since this angle is in the second quadrant, we
find the angle A by subtracting the reference angle from
or about
Now we place it in the form
(r,A) = (13,1.97), choice 2
Edwin
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