Sunday, December 18, 2016

dy/dx = 2xsqrt(4x^2+1) Use integration to find a general solution to the differential equation

For the given problem:(dy)/(dx) =2xsqrt(4x^2+1) is a first order ordinary differential equation in a form of (dy)/(dx) = f(x,y) .
 To evaluate this, we rearrange it in a form of variable separable differential equation: N(y) dy =M(x) dx .
Cross-multiply dx to the right side:dy=2xsqrt(4x^2+1)dx .
Apply direct integration on both sides: intdy= int 2xsqrt(4x^2+1)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 = 4x^2+1 then du=8x dx  or (du)/8=x dx .
The integral becomes:
int 2xsqrt(4x^2+1)dx=int 2sqrt(u)*(du)/8
                               = int (sqrt(u)du)/4
We may apply the basic integration property: int c*f(x)dx= c int f(x) dx .
int (sqrt(u)du)/4= 1/4int sqrt(u)du
Apply Law of Exponent: sqrt(x)= x^(1/2) and Power Rule for integration : int x^n= x^(n+1)/(n+1)+C .
1/4int sqrt(u)du =(1/4) int u^(1/2)du
                 =(1/4)u^(1/2+1)/(1/2+1)+C
                 =(1/4)u^(3/2)/((3/2)) +C
                  =(1/4)u^(3/2)*(2/3) +C
                  =u^(3/2)/6+C
Plug-in u=4x^2+1 on u^(3/2)/6+C , we get:
int 2xsqrt(4x^2+1)dx=(4x^2+1)^(3/2)/6+C
Combining the results from both sides, we get the general solution of the differential equation as:
y=(4x^2+1)^(3/2)/6+C

No comments:

Post a Comment

Summarize the major research findings of "Toward an experimental ecology of human development."

Based on findings of prior research, the author, Bronfenbrenner proposes that methods for natural observation research have been applied in ...