This are some problems from my practice i couldn't solve.. please help me

1. y= Ln e^4x - 1 / e^4x + 1

**is this supposed to be** $\displaystyle \ln\left(\frac{e^{4x}-1}{e^{4x}+1}\right)$

**or something else ? ... please use the correct grouping symbols.**

2. F(x) = (tan^2 x - x^2)^3

**use the chain rule ... twice.**
3. X + Ln x^2 y + 3y^2 = 2x^2 - 1

**implicit derivative ... is that one term** $\displaystyle \ln(x^2y)$

**?**
4. y= Ln(cos3x)

**derivative of** $\displaystyle \ln(u) = \frac{u'}{u}$

5. F(x) = (x+1)^1/2 - ln [1 + (x+1)^1/2]

And one integral!

(I need to solve this one by substitution) =/

1. |y^3(2y^2-3)dy

**no substitution is necessary ... distribute the** $\displaystyle y^3$ ,

**then integrate.**