1.

Which of the following is a general solution of `(d^(2)y)/(dx^(2))-2(dy)/(dx)+y=0`A. `y=(Ax+B)e^(x)`B. `y=(Ax+B)e^(-x)`C. `y=Ax^(x)+Be^(-x)`D. `y=Acos x+Bsinx`

Answer» Given that, `(d^(2)y)/(dx^(2))-2(dy)/(dx)+y=0`
`D^(2)-2Dy+y=0`
`"where" D=(d)/(dx)`
`(D^(2)-2D+1)y=0`
The auxiliary equation is `m^(2)-2m+1=0
`(m-1)^(2)+1=0`
`(m-1)^(2)=0 Rightarrow m=1,1`
Since, the roots are real and equal `CF=(Ax+B)e^(x) Rightarrow y=(Ax+B)e^(x)`
Since, if roots of Auxiliary equation are real and equal say (m), then `CF=(C_(1)x+C_(2))e^(mx)]`


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