Input:
dsolve(ds(y,t,2)=ds(y,x,2)-ds(y,x)-cos(x))
Write:
`dsolve(ds(y,t,2)=ds(y,x,2)-ds(y,x)-cos(x))`
Output: $$ dsolve(\frac{d^{{2}}y}{dt^{{2}}}=\frac{d^{{2}}y}{dx^{{2}}}-\frac{d}{dx} y-cos(x)) == C_1-\frac{1}{2}\ cos(x)-\frac{1}{2}\ sin(x)+C_3\ (\frac{1}{2}\ {t}^{2}-x)\ and\ C_1-\frac{1}{2}\ cos(x)+C_2\ exp(x)-\frac{1}{2}\ sin(x)+C_3\ (\frac{1}{2}\ {t}^{2}-x) $$ Result:$$C_1-\frac{1}{2}\ cos(x)-\frac{1}{2}\ sin(x)+C_3\ (\frac{1}{2}\ {t}^{2}-x)\ and\ C_1-\frac{1}{2}\ cos(x)+C_2\ exp(x)-\frac{1}{2}\ sin(x)+C_3\ (\frac{1}{2}\ {t}^{2}-x)$$