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# c2 Differentiation Watch

1. y=3(x-4)/2x^3
y=x^3(3x+8/x) diff these i carry on getting the wrong answer
2. (Original post by Ganhad)
y=3(x-4)/2x^3
y=x^3(3x+8/x) diff these i carry on getting the wrong answer
What answer do you get?

For the first one,

Now differentiate it.

For the second one,

Differentiate it.
3. (Original post by TheStudentBoom)
first one:

y= 3x-12/ 2x^3
y = 3x/2x^3 - 12/2x^3

y = 3/2x^2 - 6/x^3 => y= (3/2 x^-2) - (6x^-3)
dy/dx = -3x^-3 + 12x^-4

therefore dy/dx = -3/x^3 + 12/x^4

might have done something wrong there, but thats what I know. I'll do the second one in a seperate post.

By the way, please don't post full solutions. Full solutions are considered a last resort.
4. (Original post by raheem94)
What answer do you get?

For the first one,

hey the last bit is 3/2 x^-2 - 6x^-3 right? not 3/2 x^2?
5. (Original post by raheem94)

By the way, please don't post full solutions. Full solutions are considered a last resort.
Very sorry, I'll just delete my posts then.
6. (Original post by TheStudentBoom)
hey the last bit is 3/2 x^-2 - 6x^-3 right? not 3/2 x^2?
Thanks for indicating my mistake. I will edit my post.
7. (Original post by TheStudentBoom)
Very sorry, I'll just delete my posts then.
+rep to you
8. (Original post by raheem94)
+rep to you
book says something different i did get what you got -_- Damn Book could you show me this one aswell y=3sqrtx(x-2)^2
9. (Original post by Ganhad)
book says something different i did get what you got -_- Damn Book could you show me this one aswell y=3sqrtx(x-2)^2
What is the answer in the book for the previous question?
10. (Original post by Ganhad)
book says something different i did get what you got -_- Damn Book could you show me this one aswell y=3sqrtx(x-2)^2
Is this your new question
11. no the root does not go over the bracket just over the x

(Original post by raheem94)
Is this your new question
12. (Original post by Ganhad)
no the root does not go over the bracket just over the x

Now its simple to differentiate it.

By the way, what is the answer of the previous question in the book?
13. im supposed to find the gradient of that curve where x = 3 the answer is supposed to be 29root3 could you check if you get that please
14. (Original post by raheem94)

Now its simple to differentiate it.

By the way, what is the answer of the previous question in the book?
-3x^-3+6x^-4
15. (Original post by Ganhad)
im supposed to find the gradient of that curve where x = 3 the answer is supposed to be 29root3 could you check if you get that please
Which question is it?

You have posted 3 questions in this thread, which is this?
16. (Original post by Ganhad)
-3x^-3+6x^-4
Is this the answer to

If this is the case then it is wrong, the correct answer should be
17. i agree but could you see if u get 29 root 3 if you sub x=3 into
18. (Original post by Ganhad)
i agree but could you see if u get 29 root 3 if you sub x=3 into
Substituting x=3 in give

Substituting x=3 in the derivative of gives
19. this book is wak -_- so many damn mistakes
20. (Original post by raheem94)
Substituting x=3 in give

Substituting x=3 in the derivative of gives
the equation of a curve is y= x^2-5x-24/x

find the gradient of the curve at each of the point were the curve crosses the x-axis how would you do this sorry for asking for so much help but im a thicko that has been doing this for neardy 1 1/2 days straight

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