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# Core Maths 3: Differentiation using the quotient rule Watch

1. Hi there

Please could someone tell me if the below is correct;

Many thanks
Jackie
2. I haven't checked the algebra but how did you go from the fraction at the bottom left to the next stage ? The question doesn't give us x.
3. (Original post by jackie11)
Hi there

Please could someone tell me if the below is correct;

Many thanks
Jackie

Why did you wrote
4. (Original post by raheem94)

Why did you sub in x=1?
He didn't sub in x=1 otherwise the top would be 1 + 2 - 1 = 2

He could make into a proper fraction I guess.
5. (Original post by member910132)
He didn't sub in x=1 otherwise the top would be 1 + 2 - 1 = 2

He could make into a proper fraction I guess.
Thanks for correcting me, do you understand what he was trying to do?

This can easily be made into a proper fraction, but i don't think he was trying to do this.
6. (Original post by raheem94)

Why did you sub in x=1?
ok thankyou, no I just assumed that when you have the same thing on the top and bottom, i.e.

10/10, it becomes 1/1

So that's what I did for x^2/x^2 and 2x/2x
7. (Original post by jackie11)
Hi there

Please could someone tell me if the below is correct;

Many thanks
Jackie
Jackie, Jackie, Jackie

You CANNOT do that

You CANNOT cancel the x^2 and then cancel the 2x's ... NO NO NO NO
8. (Original post by jackie11)
ok thankyou, no I just assumed that when you have the same thing on the top and bottom, i.e.

10/10, it becomes 1/1

So that's what I did for x^2/x^2 and 2x/2x
10/10 becomes 1/1 but here the top has -1 and the bottom has +1.

If you want to simplify it, then you can do it in the following way,
9. (Original post by jackie11)
ok thankyou, no I just assumed that when you have the same thing on the top and bottom, i.e.

10/10, it becomes 1/1

So that's what I did for x^2/x^2 and 2x/2x
No you can't do that. say if we have , that ISN'T equal to

You can only simplify a fraction if the top and bottom are multiplied by the same factor, not 'added on' by the same amount.

E.g. the above isn't allowed, but this is:

EDIT: I'm sure you probably do know this, and are just getting confused but hopefully the examples helped
10. aww thank you all so much

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