Question

How do you solve `lnx + ln(x^2 + 1) = 8`?

Answer 1

`x≈14.37`

Explanation:

`ln(x) + ln(x^2 + 1) = 8=>`use:`log(a) + log(b) = log(ab)`

`ln[x(x^2 + 1)]=8=>`expand inside the brackets:

`ln(x^3 + x)=8=>`if:`ln(x)=y <=> x= e^y:`

`x^3+x=e^8=>`using an equation solver:

`x≈14.37`

The other two roots are not real, they are complex.