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# Implicit differentiation watch

1. Bit stuck on this as appear to have got a really odd value. I assume equation is some kind of ellipse so perhaps weird value is correct?
2. (Original post by Canary84)
Bit stuck on this as appear to have got a really odd value. I assume equation is some kind of ellipse so perhaps weird value is correct?
Two things:

What was the actual question?

The quality of your images is quite poor, and any potential errors would be difficult to spot.
3. As above, but I think you've put on your second line

.

But the original equation has no part so the part shouldn't be there.
4. Here is the question (number 1)
Attempt at re- doing working ( apologies my phone camera is a bit dodgy)

Attached Images

5. (Original post by Canary84)
Here is the question (number 1)
Attempt at re- doing working ( apologies my phone camera is a bit dodgy)
You worked out ............(1)

But then rearranged it incorrectly to get dy/dx. You have the fraction upside down.

Should be

There is actually no need to perform the division.

You're looking for when the normal has gradient 4, i.e the tangent has gradient -1/4.

So, just sub that into (1) for dy/dx. You should get x=0, and then sub into your original equation to get the possible y values.
6. (Original post by ghostwalker)
You worked out ............(1)

But then rearranged it incorrectly to get dy/dx. You have the fraction upside down.

Should be

There is actually no need to perform the division.

You're looking for when the normal has gradient 4, i.e the tangent has gradient -1/4.

So, just sub that into (1) for dy/dx. You should get x=0, and then sub into your original equation to get the possible y values.
Thanks for the help!

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