L {t2 cos t}
L[t2cost]=(−1)2d2ds2L[cost]=d2ds2(ss2+1)=2s(s2−3)(s2+1)3.L[t^2cos t]=(-1)^2\frac{d^2}{ds^2}L[cost]=\frac{d^2}{ds^2}(\frac{s}{s^2+1})=\frac{2s(s^2-3)}{(s^2+1)^3}.L[t2cost]=(−1)2ds2d2L[cost]=ds2d2(s2+1s)=(s2+1)32s(s2−3).
