1.

If`(dy)/(dx) = 1 +x +y +xy` and `y(-1)= 0` , then function `y` is :A. `e^(((1+x)^(2))/(2))-1`B. `e^(((1-x)^(2))/(2))`C. `log(1+x)-1`D. `log(1-x)`

Answer» Correct Answer - A
Let `(dy)/(dx)=1+x+y+xy`
`rArr (dy)/(dx)=(1+x)(1+y)`
`rArr (dy)/(1+y)=dx(1+x)`
`rArrint(1)/(1+y)dy=int(1+x)dx`
`rArr log(1_y)=x+(x^(2))/(2)+c`
Given
At `x=-1, y=0`
`rArr log 1=-1+(1)/(2)+c`
`rArr c=(1)/(2)`
`therefore" "log(1+y)=x+(x^(2))/(2)+(1)/(2)=((1+x)^(2))/(2)`
`rArr" "1+y=e^(((1+x)^(2))/(2))`
`rArr" "y=e^(((1+x)^(2))/(2))-1`


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