In the Taylor series
find the number a in the next term by testing at x=0
OK, so, I take the 4th derivative of u(x): u''''(x)=24 and u''''(4)=24
Now I have as my next term, but how does that help me find the constant a? I'm confused.
Ah, wait a minute, I see it.
The term has a coefficient of 1. So and