I know you have to use simultaneous equation, but I have no idea where to start. I don't think we've even covered this in class. Could anyone give me some hints on how I go about answering this question?
I know you have to use simultaneous equation, but I have no idea where to start. I don't think we've even covered this in class. Could anyone give me some hints on how I go about answering this question?
This is quite a unique question. I decided to do it by substituting one into the other.
I started by rewriting the x equation in terms of cosθ using the double angle formulae, then rearranging the y equation for cosθ. You can then do some substitution to get it just in terms of y
This is quite a unique question. I decided to do it by substituting one into the other.
I started by rewriting the x equation in terms of cosθ using the double angle formulae, then rearranging the y equation for cosθ. You can then do some substitution to get it just in terms of y
Out of interest, why are you doing C4 questions if you haven't learnt C4 yet?
This was in my homework, as are a couple of C4 reverse chain rule questions, which we have been taught in class. But we've never gone through this sort of question before.
The only identities for cos(2theta) I know of are cos^(2)theta - sin^(2)theta, 2cos^(2)theta - 1 and 1 - 2sin^(2)theta.
This was in my homework, as are a couple of C4 reverse chain rule questions, which we have been taught in class. But we've never gone through this sort of question before.
The only identities for cos(2theta) I know of are cos^(2)theta - sin^(2)theta, 2cos^(2)theta - 1 and 1 - 2sin^(2)theta.
The second one is what you need since this is only in terms of cosθ. So you have
x=2cos2θ−1
Now get y in terms of only cosθ. Then think about how you can eliminate the cosθ variable so you have an equation containing only x and y.
Ask if you still need help - don't worry if you can't do it since this type of question is new to you.