Saturday, 4 July 2015

`x^3y' + 2y = e^(1/x^2) , y(1) = e` Find the particular solution of the differential equation that satisfies the initial condition

Given,


`x^3y' + 2y = e^(1/x^2) ` and to find the particular solution of differential equation at  `y(1) = e`.


so proceeding further , we get.


`x^3 y' + 2y = e^(1/x^2)`


=>`y' + 2y/(x^3) = e^(1/x^2) /x^3`



so , the equation is linear in y


and is of the form


`y' +p(x)y=q(x)`


so the general solution is given as


`y*(I.F)= int q(x) * I.F dx+c`


where I.F (integrating factor ) =  `e^(int p(x)...

Given,


`x^3y' + 2y = e^(1/x^2) ` and to find the particular solution of differential equation at  `y(1) = e`.


so proceeding further , we get.


`x^3 y' + 2y = e^(1/x^2)`


=>`y' + 2y/(x^3) = e^(1/x^2) /x^3`



so , the equation is linear in y


and is of the form


`y' +p(x)y=q(x)`


so the general solution is given as


`y*(I.F)= int q(x) * I.F dx+c`


where I.F (integrating factor ) =  `e^(int p(x) dx)`


on comparing we get ,


`p(x) = 2/x^3 and q(x) = e^(1/x^2) /x^3`


so ,


`I.F = e^(int (2/x^3) dx) = e^(2 (x^-3+1 )/ -2) = e^(-(x^-2))`


so ,


`y (e^(-(x^-2)))= int (e^(1/x^2) /x^3) * (e^(-(x^-2))) dx+c`


=>`y (e^(-(x^-2)))= int (x^-3) dx+c`


=>`y (e^(-(x^-2)))= x^((-3+1)/ -2)+c`


=> `y (e^(-(x^-2)))= x^-2/ -2+c`


=> `y = (- (x^-2)/2+c)/(e^(-(x^-2))) `


= `e^((x^-2)) *(c-(x^-2)/2 )`


so , now to find the particular soultion at `y(1) =e` , we have to do as follows


`y(x) = e^((x^-2)) *(c-(x^-2)/2 )`


=> y(1) = `e^((1^-2) ) *(c-(1^-2)/2 )`


=> `e= (e ) *(c-(1)/2 )`


=> `1= c-1/2`


=> `c= 3/2`


so the particular solution is


`y= ((e^((x^-2))) ) *(3/2-(x^-2)/2 )`


=`e^((x^-2)) *((3-(x^-2))/2 )`


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