# Math Help - Help with simple differentiation

1. ## Help with simple differentiation

Hi,
How do I solve for the following: $d/dx [(0.1x + 0.4)log(0.1x + 0.4)]?$

I got the following answer but I think its wrong: $(1/ln2) + 0.1log(0.1x + 0.4).$

Can somebody help?

2. what base log are you using ?