Question

Part 3 please help ​

Answer 1

I'm taking "part 3" to mean the 3rd of the posted questions.

If $f(x)=(x^3+2x)\ln x$, then

$f'(x)=(x^3+2x)'\ln x+(x^3+2x)(\ln x)'=(3x^2+2)\ln x+\dfrac{x^3+2x}x$

$\implies f'(x)=(3x^2+2)\ln x+x^2+2$

Then when $x=1$, we get $f'(1)=3$.