Thursday 14 November 2013

`y' + ytanx = secx + cosx , y(0) = 1` Find the particular solution of the differential equation that satisfies the initial condition


Given` y'+ytanx=secx+cosx`


when the first order linear ordinary Differentian equation has the form of


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


then the general solution is ,


`y(x)=((int e^(int p(x) dx) *q(x)) dx +c)/ e^(int p(x) dx)`


so,


`y'+ytanx=secx+cosx--------(1)`


`y'+p(x)y=q(x)---------(2)`


on comparing both we get,


`p(x) = tanx and q(x)=secx +cosx`


so on solving with the above general solution we get:


y(x)=`((int e^(int p(x) dx) *q(x)) dx +c)/e^(int p(x) dx)`


=`((int e^(int (tanx) dx) *(secx+cosx)) dx +c)/e^(int tanx dx)`


first we...



Given` y'+ytanx=secx+cosx`


when the first order linear ordinary Differentian equation has the form of


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


then the general solution is ,


`y(x)=((int e^(int p(x) dx) *q(x)) dx +c)/ e^(int p(x) dx)`


so,


`y'+ytanx=secx+cosx--------(1)`


`y'+p(x)y=q(x)---------(2)`


on comparing both we get,


`p(x) = tanx and q(x)=secx +cosx`


so on solving with the above general solution we get:


y(x)=`((int e^(int p(x) dx) *q(x)) dx +c)/e^(int p(x) dx)`


=`((int e^(int (tanx) dx) *(secx+cosx)) dx +c)/e^(int tanx dx)`


first we shall solve


`e^(int (tanx) dx)=e^(ln(secx))= secx `     


so proceeding further, we get


`y(x) =((int e^(int (tanx) dx) *(secx+cosx)) dx +c)/e^(int tanx dx)`


=`((int secx *(secx+cosx)) dx +c)/(secx )`


=`((int (sec^2 x+cosxsecx)) dx +c)/(secx )`


= `((int (sec^2 x)dx +int 1 dx) +c)/secx`

=` (tanx+x +c)/secx`


=` sinx +(x+c)/secx`


`y(x) = sinx +(x+c)/secx`




to find the particular solution of the differential equation we have `y(0)=1`



on substituting x=0 we get y=1 and so we can find the value of the c


`y(0)= sin0+(0+c)/sec0 =0+0+c/1 = c`


but `y(0)=1`


=> `1=c`


=> `c=1 `


so `y=sinx+(x+1)/secx` 

No comments:

Post a Comment

In "By the Waters of Babylon," under the leadership of John, what do you think the Hill People will do with their society?

The best place to look for evidence in regards to what John's plans are for his people is the final paragraphs of the story. John has re...