Laplace transforms problem sin3t+cos3t

Question

amistre64 · Answer

have you got a table setup?

amistre64 · Answer

otherwise its just a matter if integrateing a by parts with e^(-st)

amistre64 · Answer

$$\large\int sin(at)~e^{-st}~dt$$
   sin(at)        -e^(-st)/s
a cos(at) dt     e^(-st) dt

$$\large -\frac{1}{s}e^{-st}~sin(at)+\frac{a}{s}\int cos(at)~e^{-st}~dt$$
    cos(at)            -e^(-st)/s
-a sin(at) dt     e^(-st) dt

etc ...

amistre64 · Answer

at 0 and infinity i believe that first term goes zero .....

anonymous · Answer

someone help me with this please

unklerhaukus · Answer

$$\mathcal L\Big\{\sin (nt)\Big\}(s)=\frac{n}{s^2+n^2}$$
$$\mathcal L\Big\{\cos (nt)\Big\}(s)=\frac{s}{s^2+n^2}$$

amistre64 · Answer

please do not post your own question into someone elses post .... butyes, someone can help with that