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6522318 No.6522318[DELETED]  [Reply] [Original]

What would be equation of these lines in polar system, if it is known that in cartesian coordinate system one of them crosses Ox axis at 30 degrees and other at 120 degrees.

>> No.6522338

bump

>> No.6522352

>>6522338
I'm not sure if I get your question completely, but I'll try.
y=.5x is a line that forms a 30 degree angle with the x axis.
Using the @ sign for theta (I'm on my phone),
rsin@=y and rcos@=x
Substituting,
rsin@=.5rcos@
Ergo 0.5=tan@
Qed

>> No.6522360

>>6522318
write the equations down in cartesian coordinates. Subsitute your variables with the appropriate polar coordinate representation. Now some algebraic stuff and your finished.
Reminder: x = r*cos(phi), y = r*sin(phi)

>> No.6522387

flat line => y = c

as mentioned above y = r*sin@ so it follows that

r*sin@ = c

there are infinite solutions

>> No.6522492

I have two equations - theta=pi/6 and theta=2pi/3.

How do I get the r out of them (I need r to calculate integral)?

>> No.6522560

Is this linked to a previous post? If not then I don't believe you can calculate r.

>> No.6522563

>>6522560
>>6522492
forgot

>> No.6522659

>>6522560
>>6522563
Yes. I have to lines: y=0.5x and y=-2x
If I try to calculate r by this method >>6522352
I get 0.
I tried messing in polar function grapher and found out that theta=pi/6 and theta=2pi/3 represents those two lines. I guess I'll give up on this task

>> No.6522700

<span class="math">/theta[/spoiler]