矩阵的级数：
定义：
[{e^{tA}} = I + frac{{tA}}{{1!}} + frac{{{t^2}{A^2}}}{{2!}} + ... + frac{{{t^k}{A^k}}}{{k!}} + ...]
[sin (tA) = tA - frac{{{t^3}{A^3}}}{{3!}} + ... + {( - 1)^k}frac{{{t^{2k + 1}}{A^{2k + 1}}}}{{(2k + 1)!}} + ...]
[cos (tA) = I - frac{{{t^2}{A^2}}}{{2!}} + ... + {( - 1)^k}frac{{{t^{2k}}{A^{2k}}}}{{(2k)!}} + ...]