2.2.89 Derivatives and Differentials
Condition: check whether the specified equation satisfies this function \ (U \). \ [a^{2} \ frac {\ partial^{2} u} {\ partial x^} {2} = \ frac {\ partial^{2} u} {\ partial y^{2}}, \ quad u = \ sin ^{2} (x-a y) \]
Calculation of derivatives and differentials of first and Higher Orders of Function of One and Many Varia Bybles, Including Partial Derivatives.