# For the lovers of maths!

Calculus Level pending

Consider,

$S = 2 \left [1+x+\sum_{k=1}^{\infty}{ \left(\dfrac{x^{(4k)}}{(4k)!}+\dfrac{x^{(4k+1)}}{(4k+1)!} \right)} \right ]$

If $$S=0$$, then find all possible numbers of solution for $$-6 < x < 0$$.

×