ydy+xe^xcos^2ydx=0

To solve the differential equation:

ydy + xe^(x * cos^2(y))dx = 0

First, we need to check if it is a separable differential equation. A separable differential equation is one that can be written in the form f(y)dy = g(x)dx, where f(y) is a function of y only, and g(x) is a function of x only.

In this case, we can rewrite the equation as:

ydy = -xe^(x * cos^2(y))dx

Now, we can separate the variables by dividing both sides of the equation by y and multiplying both sides by dx:

(1/y)dy = -xe^(x * cos^2(y))dx

Next, we integrate both sides of the equation.

∫(1/y)dy = ∫-xe^(x * cos^2(y))dx

The integral on the left side is relatively straightforward:

ln|y| + C1 = ∫-xe^(x * cos^2(y))dx

Now, let's focus on the integral on the right side. This integral appears to be more complex and does not have a standard solution. To solve this, we can use numerical methods or approximation techniques, such as power series expansion, to find an approximate solution.

Keep in mind that solving this integral will require more advanced mathematical techniques, and it may not have a simple closed-form solution.

In summary, we have transformed the given equation into a separable form, but solving the resulting integral ∫-xe^(x * cos^2(y))dx will require using numerical methods or approximation techniques.

The integral of y/cos^2y dy

= The integral of e*e^x dx
+ Constant

y tany + log(cosy) = e^x*(x-1) + C
Use an initial condition to evaluate C

Verify the integrals yourself. I used a table of integrals.