Can you make 'P' the subject please?

Hi,

I'm stuck on this! Have had several attempts but can't arrive at the given solution. I've no propensity for maths!

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Any help gratefully appreciated.

Hi,

That's an ellipse.

p^2=x^2/(1-y^2/q^2)

so

p1=sqrt(x^2/(1-y^2/q^2)), y^2/q^2!=1
p2=-sqrt(x^2/(1-y^2/q^2)), y^2/q^2!=1

BTW, p is the distance along the x axis from the center to each edge of the ellipse.

Hello Mr Al,

Don't know if your still around. Thanks for your prompt reply earlier.

Is this how you arrived at your solution?

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That was one of the solutions that I arrived at but the solution in the text book is:

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Actually, in the text book solution the x is X (capitalised). Must be a typo. Is the solution correct?

Thanks again.

Hi again,


Oh ok, well that requires one little extra step then...

starting again with:

p^2=x^2/(1-y^2/q^2)

multiply the top and bottom of the right side by q^2 to get:

p^2=x^2*q^2/(q^2-y^2)

Now when we take the square root we can perform this
on the top but not on the bottom so we get:

p=x*q/sqrt(q^2-y^2)

Ok now?

Hi,

Thanks. I can follow your working, I'd never have 'seen' the way to proceed.