Input:
pdsolve(ds(y,t,2)-a^2*ds(y,x,2)-a^2*ds( y,u,2)-a^2*ds(y,v,2))
Write:
`pdsolve(ds(y,t,2)-a^2*ds(y,x,2)-a^2*ds( y,u,2)-a^2*ds(y,v,2))`
Compute:
$$pdsolve(\frac{d^{{2}}y}{dt^{{2}}} - {a}^{2}\ \frac{d^{{2}}y}{dx^{{2}}} - {a}^{2}\ \frac{d^{{2}}y}{du^{{2}}} - {a}^{2}\ \frac{d^{{2}}y}{dv^{{2}}})$$
Output:
$$pdsolve(\frac{d^{{2}}y}{dt^{{2}}} - {a}^{2}\ \frac{d^{{2}}y}{dx^{{2}}} - {a}^{2}\ \frac{d^{{2}}y}{du^{{2}}} - {a}^{2}\ \frac{d^{{2}}y}{dv^{{2}}})== C_1+C_2\ exp(1.7320508075688774i\ t)\ sin(u)\ sin(v)\ sin(x)+C_3\ (\frac{3}{2}\ {t}^{2}+u+\frac{1}{2}\ {u}^{2}+v+\frac{1}{2}\ {v}^{2}+x+\frac{1}{2}\ {x}^{2})$$
Result: $$C_1+C_2\ exp(1.7320508075688774i\ t)\ sin(u)\ sin(v)\ sin(x)+C_3\ (\frac{3}{2}\ {t}^{2}+u+\frac{1}{2}\ {u}^{2}+v+\frac{1}{2}\ {v}^{2}+x+\frac{1}{2}\ {x}^{2})$$
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