# what's the taylor serie and it's convergence

I have this problem:

What is the Taylor series of $\sqrt{x}$ at $x_0 = 4$. What is its interval of convergence?

I am stuck and I can not finish it.

Any idea on how to do that?

Thank you

• What have you done so far? – Aretino Dec 2 '15 at 22:28
• @Aretino nothing important, just small tests that do not conclude to a final result. – zeeks Dec 2 '15 at 22:37
• If you know the answer for $\sqrt{1+t}$ at $0$, write $x=x_0+h=4+h$, and deal with $\sqrt{4+h} = 2\sqrt{1+h/4}$ instead. – Clement C. Dec 2 '15 at 22:39