Find the first partial derivatives of the function. f(x, t) = e−9t cos(πx)

Step-by-step explanation:

We are given the following function:

First derivatives:

We find the first derivatives in function of x and of t.

Function of x:

The exponential is only a function of t, so it is treated as a constant.

Function of t:

Same logic as above, the cosine as treated as a constant.

check the picture below.