How do you convert x=3 into a polar equation?

1 Answer
A. S. Adikesavan
Apr 22, 2016

#r=3 sec theta#.

Explanation:

#x=r cos theta#
So, x =3 becomes #r cos theta = 3 or r = 3 sec theta#

x = 3 is the straight line parallel to y-axis, in the first and fourth quadrants, at a distance 3 from the y-axis.

The polar forms of lines parallel to the axes are #r = a sec theta, theta in (-pi/2, pi/2) and r = a csc theta, theta in (pi, 0)#.
r ranges from #+oo# down to a and increase to # +oo#.

Unless necessitated (in problems relating to radial directions), polar forms are avoided for equations of straight lines . .

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