CONVERT RECTANGULAR COORDINATES INTO POLAR FORM

Let P be the rectangular coordinate in the form (x, y), we should convert it into the form of (r, θ).

Then,

r2  =  x2 + y2

θ  =  tan-1 (y/x)

To find the general solution,

θ  =  tan-1 (y/x) + nπ

Example 1 :

Convert to polar coordinates on the interval 0 < θ < 2π

(a)  (-1, 1)    (b)  (1, √3)

Solution :

(a)  (-1, 1) 

x  =  -1 and y  =  1

r2  =  x2 + y2

r2  =  12 + 12

r2  =  2

r  = ± √2 

θ  =  tan-1 (y/x)

θ  =  tan-1 (-1/1)

θ  =  tan-1 (-1)

θ  =  -π/4

If r  =  √2 then  θ  =  -π/4  ==>  (√2, -π/4)

If r  =  -√2 then  θ  =  -π/4 + π  ==>  (√2, 3π/4)

If r  =  √2 then  θ  =  -π/4 + 2π  ==>  (√2, 7π/4)

(b)  (1, √3)

x  =  1 and y  =  √3

r2  =  x2 + y2

r2  =  12 + √32

r2  =  1 + 3

r2  =  4

r  =  ±2

θ  =  tan-1 (y/x)

θ  =  tan-1 (1/1)

θ  =  tan-1 (1)

θ  =  π/4 


If r  =  2 then  θ  =  π/4  ==>  (2, π/4)

If r  =  -2 then  θ  =  π/4 π  ==>  (-2, 5π/4)

If r  =  2 then  θ  =  π/4 + 2π  ==>  (2, 9π/4)

If we have any restriction like the angle must between 0 to 360, then we have to ignore the last option.

Example 2 :

Convert the given rectangular coordinate to polar coordinate between 0 ≤ θ ≤ 2π

(1, -√3) 

x  =  1 and y  =  -√3

r2  =  x2 + y2

r2  =  12 + (-√3)2

r2  =  1 + 3

r2  =  4

r  =  ±2

θ  =  tan-1 (y/x)

θ  =  tan-1 (-√3/1)

θ  =  tan-1 (-√3)

θ  =  -π/3 


If r  =  2 then  θ  =  -π/3  ==>  (2, -π/3)

If r  =  -2 then  θ  =  -π/3 π  ==>  (-2, 2π/3)

If r  =  2 then  θ  =  -π/3 + 2π  ==>  (2, 5π/3)

Kindly mail your feedback to v4formath@gmail.com

We always appreciate your feedback.

©All rights reserved. onlinemath4all.com

Recent Articles

  1. Digital SAT Math Problems and Solutions (Part - 213)

    Jul 13, 25 09:51 AM

    digitalsatmath292.png
    Digital SAT Math Problems and Solutions (Part - 213)

    Read More

  2. Digital SAT Math Problems and Solutions (Part - 212)

    Jul 13, 25 09:32 AM

    digitalsatmath290.png
    Digital SAT Math Problems and Solutions (Part - 212)

    Read More

  3. Digital SAT Math Problems and Solutions (Part - 211)

    Jul 11, 25 08:34 AM

    digitalsatmath289.png
    Digital SAT Math Problems and Solutions (Part - 211)

    Read More