$${8 \over {{\pi ^2}}}\left[ {\sin \left( {\pi t} \right) + {1 \over 9}\sin \left( {3\,\pi t} \right) + {1 \over {25}}\sin \left( {5\,\pi t} \right) + ........} \right]$$

$${8 \over {{\pi ^2}}}\left[ {\sin \left( {\pi t} \right) - {1 \over 9}\cos \left( {3\,\pi t} \right) + {1 \over {25}}\sin \left( {5\,\pi t} \right) + ........} \right]$$

$${8 \over {{\pi ^2}}}\left[ {\cos \left( {\pi t} \right) + {1 \over 9}\cos \left( {3\,\pi t} \right) + {1 \over {25}}\cos \left( {5\,\pi t} \right) + ........} \right]$$

$${8 \over {{\pi ^2}}}\left[ {\cos \left( {\pi t} \right) - {1 \over 9}\sin \left( {3\,\pi t} \right) + {1 \over {25}}\sin \left( {5\,\pi t} \right) + ........} \right]$$

$${d \over {d\,t}}\int\limits_0^t s \left( {t - \tau } \right)\,u\left( \tau \right)\,d\,\tau $$

$$\int\limits_0^t s \left( {t - \tau } \right)\,u\left( \tau \right)\,d\,\tau $$

$$\int\limits_0^t {\int\limits_0^\tau s \left( {t - {\tau _1}} \right)\,u\left( {{\tau _1}} \right)\,d{\tau _1}} \,d\tau $$

$${d \over {d\,t}}\int\limits_0^t h \left( {t - \tau } \right)\,u\left( \tau \right)\,d\,\tau $$

$$\underset{s\rightarrow0}{L\mathrm{im}\;}Y\left(s\right)$$

$$\underset{s\rightarrow\infty}{L\mathrm{im}\;}Y\left(s\right)$$

$$\underset{s\rightarrow0}{L\mathrm{im}\;}sY\left(s\right)$$

$$\underset{s\rightarrow\infty}{L\mathrm{im}\;}sY\left(s\right)$$