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# Trig question

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1. x = 1 - sinθ

y = 1 + cosθ

Need to rewrite this pair as one equation in terms of x and y, I tried all possible identities but couldn't do it, what would you do for this?
2. I'm not sure I understand the question. What comes to my mind is a parametric curve.

That would result in a circle of equation
3. The question before that one was as follows:

x = 4secθ

y = 2tanθ

And the answer was x^2= 16 + 4y^2

It's asking to combine both equations together so it's written in terms of x and y only.
4. And just looking at your post now, I see it simply forms sin^2 + cos^2 which equals 1 and it's in terms of x and y, thank you very much
5. (Original post by Rexx18)
The question before that one was as follows:

x = 4secθ

y = 2tanθ

And the answer was x^2= 16 + 4y^2

It's asking to combine both equations together so it's written in terms of x and y only.
So it really is about parametric curves.

Recall that

If you square your equations for and , you get and

Isolating and , and plugging them back in the trig identity, you should get the formula for the hyperbola.

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Updated: October 10, 2016
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