An ordinary differential equation (ODE) is differential equation for the derivative of a function of one variable. When an ODE is in a form of `y'=f(x,y)` , this is just a first order ordinary differential equation.
We may express `y' ` as `(dy)/(dx) ` to write in a form of `(dy)/(dx)= f(x,y)` and apply variable separable differential equation: `N(y)dy = M(x) dx` .
The given problem: ` (dy)/(dx) = xe^(x^2) ` can be rearrange as:
`dy= xe^(x^2) dx`
Apply direct integration on both sides:
`int dy= int xe^(x^2) dx`
For the left side, we apply basic integration property: `int (dy)=y` .
For the right side, we may apply u-substitution by letting: `u = x^2` then `du =2x dx` or `(du)/2=x dx` .
The integral becomes:
`int xe^(x^2) dx=int e^(x^2) *xdx`
` =int e^(u) *(du)/2`
Apply the basic integration property: `int c*f(x)dx= c int f(x) dx` .
`int e^(u) *(du)/2=(1/2)int e^(u) du`
Apply basic integration formula for exponential function:
`(1/2)int e^(u) du=(1/2)e^(u)+C`
Plug-in `u=x^2` on `(1/2)e^(u)+C` , we get:
`int xe^(x^2) dx=(1/2)e^(x^2)+C`
Combining the results from both sides, we get the general solution of differential equation as:
`y=(1/2)e^(x^2)+C`
or
`y=e^(x^2)/2+C`
No comments:
Post a Comment