About Taylor series of function

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Let us consider the function defined by

[![function defined by ][1]][1]

We have f(0)=0 How we show that f(x) is not equal to it's Taylor expansion at x=O

I try to get coefficients, $c_0 = 0$, $c_1= $enter image description here

[1]: https://i.stack.imgur.com/MDeRD.jpg unable to find this limit, please tell me how i prove this...

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You can show that $$f^{(n)}(0)=0$$

which means that the Taylor expansion of $f$ at $x=0$ is

$$\sum_{n=0}^\infty f^{(n)}\frac{x^n}{n!} = \sum_{n=0}^\infty 0 = 0$$

and $0$ (the Taylor expansion of $f$) is clearly not equal to $f$.