Active forum topics
- Inverse Trigo
- General Solution of $y' = x \, \ln x$
- engineering economics: construct the cash flow diagram
- Eliminate the Arbitrary Constants
- Law of cosines
- Maxima and minima (trapezoidal gutter)
- Special products and factoring
- Integration of 4x^2/csc^3x√sinxcosx dx
- application of minima and maxima
- Sight Distance of Vertical Parabolic Curve
New forum topics
- Inverse Trigo
- General Solution of $y' = x \, \ln x$
- engineering economics: construct the cash flow diagram
- Integration of 4x^2/csc^3x√sinxcosx dx
- Maxima and minima (trapezoidal gutter)
- Special products and factoring
- Newton's Law of Cooling
- Law of cosines
- Can you help me po to solve this?
- Eliminate the Arbitrary Constants
Recent comments
- Yes.4 weeks ago
- Sir what if we want to find…4 weeks ago
- Hello po! Question lang po…1 month 2 weeks ago
- 400000=120[14π(D2−10000)]
(…2 months 2 weeks ago - Use integration by parts for…3 months 2 weeks ago
- need answer3 months 2 weeks ago
- Yes you are absolutely right…3 months 3 weeks ago
- I think what is ask is the…3 months 3 weeks ago
- $\cos \theta = \dfrac{2}{…3 months 3 weeks ago
- Why did you use (1/SQ root 5…3 months 3 weeks ago
We need to reaarange the
We need to reaarange the differential equation so that it can be solved easily...
$$\left( x \csc\left( \frac{y}{x}\right) - y\right) dx + x dy = 0$$
$$x \csc\left( \frac{y}{x}\right)dx - ydx + xdy = 0$$
$$xdy = -x \csc\left( \frac{y}{x}\right)dx + ydx$$
Divide the terms of the differential equation by $x$, getting:
$$dy = - \csc\left( \frac{y}{x}\right)dx + \left( \frac{y}{x}\right)dx$$
Apparently this modified form of differential equation is a homogenous differential equation. So we let $v = \frac{y}{x}$, $y = vx$ and
$dy = vdx + xdv$. So we get:
$$dy = - \csc\left( \frac{y}{x}\right)dx + \left( \frac{y}{x}\right)dx$$
$$vdx + xdv = - \csc(v)dx + vdx$$
$$ xdv = - \csc(v)dx$$
$$\frac{dv}{-\csc(v)} = \frac{1}{x} dx$$
$$-sin(v)dv = \frac{1}{x} dx$$
The above differential equation is now a variable-separable type...so we get the integral of individual terms.
$$-sin(v)dv = \frac{1}{x} dx$$
$$\int -sin(v)dv = \int \frac{1}{x} dx$$
$$cos(v) + c_1 = ln(x) + c_2$$
$$cos(v) = ln(x) + c_2 - c_1$$
$$cos(v) = ln(x) + C$$
Now getting the $v$:
$$cos(v) = ln(x) + C$$
$$v = cos^{-1}(ln(x) + C)$$
The solution of the given differential equation $\left( x \csc\left( \frac{y}{x}\right) - y\right) dx + x dy = 0$ would be:
$$y = vx$$
$$y = (cos^{-1}(ln(x) + C))x$$
$$y = xcos^{-1}(ln(x) + C)$$
Alternate ways of answering it are encouraged....