Question

Write -2x+4y=9 in polar form using the polar form of a linear equation.

Answer 1

i'm troubled, getting phi.
I don't know when to add 180 to the Arctan

Answer 2

You'll use these two equations
\[\Large x = r\cos(\theta)\]
\[\Large y = r\sin(\theta)\]


\[\Large -2x + 4y = 9\]
\[\Large -2*r\cos(\theta) + 4*r\sin(\theta) = 9\]
Now solve for r

Answer 3

ok so for p I got \[\frac{ -9\sqrt{5} }{ 10}\]

Answer 4

and for phi, i got -63.43 @jim_thompson5910

Answer 5

should I add 180, and can you explain to me when should I add it

Answer 6

how are p and phi defined?

Answer 7

no idea