2.2.86 Derivatives and Differentials

Condition: Calculate the value of the derivative of a complex function \ (u = u (x, y) \), where \ (x = x (t), y = y (t) \), with \ (t_ {0} \) with an accuracy of two signs after the decoration. \ [u = x^{y}, \ quad x = e^{t}, \ quad y = \ ln t, \ quad t_ {0} = 1 \]