I have this problem:

y'= x+y , with y(0)=1

I am asked to estimate y when x=0.4 using Taylor series to the 5th power.

However, I am in a jam, because I don't understand how I am to do this while having 2 variables to differentiate.

Can someone please show how to differentiate at least for the 1st step to get y''? All I know is that the Taylor series will start with "1+....", I think.

Thank you,

Jen