theta=3pi/4. Find in rectangular form?

Question

primeralph · Answer

No r value?

anonymous · Answer

no

anonymous · Answer

would the answer be tan(3pi/4)=-1

primeralph · Answer

@Directrix Please do this.

directrix · Answer

theta=3pi/4
inverse tangent of (y/x) = 3pi/4
y/x = tan(3pi/4)
y/x = -1
Therefore, the rectangular equation for the polar equation theta=3pi/4
will be:

y = -x --> a line

@mutantkiller  Check my work and yours, too. I used this calculation you did above: tan(3pi/4)=-1

primeralph · Answer

@Directrix  I thought of that too as an infinite line, but for some reason, I expected a ray.

anonymous · Answer

i have one other question

anonymous · Answer

how do you change x+y=2 into polar form?

directrix · Answer

@primeralph  I pondered that same question. I have seen theta = some angle graphed as a ray and then as that same ray with the ray opposite it, forming a line. l I don't know that there is clarity on that issue. I need to do some reading.

primeralph · Answer

@Directrix  Sometimes the basic stuff gets us too.

@mutantkiller  Just put x =rcostheta and y =rsinetheta and simplify if possible.

anonymous · Answer

ok thanks

primeralph · Answer

You're welcome.