# Math Help - Differention help

1. ## Differention help

Hi, I was wondering if you could help me out with a few problems

1)log (3x+8x^3)
2)3sqrr(2x-1)
3)e^x.cosecx
4)e^(4x+3)/4x+3
5)find g'''(x) when g(x)=7x^3-2x^2+4x-8
6)If x=sin(x) y= sec(x) find dy/dx
7)x=t^2 y=2t + 1
find the equation of the tangent at the point where t=2

I ended up with
1)24x^2 + 3/3x+8x^3
2)2/3(2x-1)^-2/3
3)-cosecxcotx.e^x + cosec.e^x
4)4e^4x+3(4x+3)-4e^4x+3/(4x+3)^2
5)42
6)sec(x).tan(x)/cos(x)
7)1/2x + 3

2. 1. Assuming you meant (24x^2 + 3)/(3x + 8x^3), then yes, you are correct. Brackets are ESSENTIAL!

2. Incorrect.

3. Correct

4. I suspect you have again not used brackets correctly. Please fix it so that I can read it.

5. Correct

6. What on earth are you using "deg" to represent?

7. Correct.

3. Originally Posted by Prove It
1. Assuming you meant (24x^2 + 3)/(3x + 8x^3), then yes, you are correct. Brackets are ESSENTIAL!

2. Incorrect.

3. Correct

4. I suspect you have again not used brackets correctly. Please fix it so that I can read it.

5. Correct

6. What on earth are you using "deg" to represent?

7. Correct.
Thanks for the feedback