Solve Bernoulli's equation 2 x^3 ( dy(x))/( dx) = (2 x^2 - y(x)^2) y(x):
Rewrite the equation:
2 x^3 ( dy(x))/( dx) - 2 x^2 y(x) = -y(x)^3
Divide both sides by -x^3 y(x)^3:
-(2 ( dy(x))/( dx))/y(x)^3 + 2/(x y(x)^2) = 1/x^3
Let v(x) = 1/y(x)^2, which gives ( dv(x))/( dx) = -(2 ( dy(x))/( dx))/y(x)^3:
( dv(x))/( dx) + (2 v(x))/x = 1/x^3
Let μ(x) = e^( integral2/x dx) = x^2.
Multiply both sides by μ(x):
x^2 ( dv(x))/( dx) + (2 x) v(x) = 1/x
Substitute 2 x = d/( dx)(x^2):
x^2 ( dv(x))/( dx) + d/( dx)(x^2) v(x) = 1/x
Apply the reverse product rule f ( dg)/( dx) + g ( df)/( dx) = d/( dx)(f g) to the left-hand side:
d/( dx)(x^2 v(x)) = 1/x
Integrate both sides with respect to x:
integral d/( dx)(x^2 v(x)) dx = integral1/x dx
Evaluate the integrals:
x^2 v(x) = log(x) + c_1, where c_1 is an arbitrary constant.
Divide both sides by μ(x) = x^2:
v(x) = (log(x) + c_1)/x^2
Solve for y(x) in v(x) = 1/y(x)^2:
Answer: |
| y(x) = -x/sqrt(log(x) + c_1) or y(x) = x/sqrt(log(x) + c_1)
это вывод какого приложения?