13whispers
New member
- Joined
- Apr 17, 2018
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- 3
Write each equation in polar coordinates. Express as a function of t. Assume that r>0.
x^2+y^2+5x=0
x^2(x^2+y^2)=7y^2
x^2+y^2+5x=0
x^2(x^2+y^2)=7y^2
For problem (1) - rewrite as:Write each equation in polar coordinates. Express as a function of t. Assume that r>0.
x^2+y^2+5x=0
x^2(x^2+y^2)=7y^2
Interesting problem. Exactly do you need help with? What have you tried?Write each equation in polar coordinates. Express as a function of t. Assume that r>0.
x^2+y^2+5x=0
x^2(x^2+y^2)=7y^2
Write each equation in polar coordinates. Express as a function of t. Assume that r>0.
x^2+y^2+5x=0
x^2(x^2+y^2)=7y^2
I figured out the first one.
For x^2(x^2+y^2)=7y^2, here's what I'm doing:
x^2(r^2)=7y^2
(rcost)^2(r^2)=7(rsint)^2
r^2=[7(rsint)^2]/(rcost)^2
r=sqrt(7tant^2)
I'm not sure where I'm going wrong. FYI, I'm entering the answer into Webwork, which is sometimes picky about the form of the answer.
If you typed it in just as you show here, it would definitely be unhappy.
Assuming you are supposed to use t in place of theta, your last line should look like this, where I am being careful to show what is being squared:
r = sqrt(7 (tan(t))^2)
It is not t, but its tangent, that is squared. (Traditionally, we would write this part as tan^2 t, but a computer likely would not allow that.)
You could further simplify this, by breaking up the radical; that may or may not be demanded. Note that since you are told to assume that r>0, you can simplify the root of a square without worrying about signs.
If it still doesn't take your answer after fixing these two things, tell me exactly what you typed in, maybe even with a screen shot. Apart from these issues, your work looks good.