What is wrong with this maclauren series?

[jayz]

Whats wrong with my answer?

Q. Find \(\displaystyle T_4 (x)\): the Taylor polynomial of degree 4 of the function \(\displaystyle f(x)\, =\, \arctan(7x)\) at \(\displaystyle a\, =\, 0.\)

My A. \(\displaystyle \left(7x\, -\, \dfrac{343x^3}{3}\, +\, \dfrac{16807x^5}{5}\, -\, \dfrac{823543x^7}{7}\, +\, \dfrac{(4.03536\, \times\, 10^7)x^9}{9}\right)\pi\)

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[stapel]

Are you maybe expected to simplify where possible?

 

[Ishuda]

Whats wrong with my answer?

Q. Find \(\displaystyle T_4 (x)\): the Taylor polynomial of degree 4 of the function \(\displaystyle f(x)\, =\, \arctan(7x)\) at \(\displaystyle a\, =\, 0.\)

My A. \(\displaystyle \left(7x\, -\, \dfrac{343x^3}{3}\, +\, \dfrac{16807x^5}{5}\, -\, \dfrac{823543x^7}{7}\, +\, \dfrac{(4.03536\, \times\, 10^7)x^9}{9}\right)\pi\)

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Unless it is the simplification staple mentioned, I think I would quit using that particular tool [I might anyway]. The 823543/7 can be simplified to 117649

Oh, and what is that \(\displaystyle \pi\) I keep seeing hanging around the end of the equations?