x Turn on thread page Beta
 You are Here: Home >< Maths

# Is this correct? watch

1. Differentiate y = 3x^5 +4x^2 -8x all over 2x

I ger rid of the fraction by turning the 2x into an indice amd getting 3x^5 +4x^2 - 8x + 2x^-1 and they doing dy/dx i get15x^4 +8x -8 + -2x^-2 ?
2. You can take out X as a factor.
So y=1.5x^2 + 2x - 4
dy/dx=3x+2
3. (Original post by Caramelchan)
You can take out X as a factor.
So y=1.5x^2 + 2x - 4
dy/dx=3x+2
Shoudnt the 1.5x^2 become 1.5x^3 ?
4. (Original post by hazbaz)
Shoudnt the 1.5x^2 become 1.5x^3 ?
The power decreases when you differentiate (and even if you were integrating it wouldn't become 1.5x³).
5. (Original post by nuodai)
The power decreases when you differentiate (and even if you were integrating it wouldn't become 1.5x³).
Ok and i don't know abut intergration yet im only on C1 haha.
6. (Original post by hazbaz)
Differentiate y = 3x^5 +4x^2 -8x all over 2x

I ger rid of the fraction by turning the 2x into an indice amd getting 3x^5 +4x^2 - 8x + 2x^-1 and they doing dy/dx i get15x^4 +8x -8 + -2x^-2 ?

You'll be better off noticing that there is a common factor of in , pull it out and it will cancel with the x in the denominator.
i.e.:
and then differentiate that.
7. (Original post by hazbaz)
Shoudnt the 1.5x^2 become 1.5x^3 ?
Hahah I did a fail and read the ^5 as ^3 so sorry
But yeah. You've got an answer now

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: September 30, 2010
Today on TSR

### Four things top students are doing

Over the Easter break

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams