Question

Let `y=in (1+ cos x)^(2).` The the value of `(d^(2)y)/(dx^(2))+(2)/(e^(y//2))` equals

Answer 1

`y=2" In "(1+ cos x)`
`(dy)/(dx)=(-2 sin x)/(1+cos x)`
`(d^(2)y)/(dx^(2))=-2[((1+cos x)cos x- sin x(-sin x))/((1+cos x)^(2))]`
`=-2[(cos x +1)/((1+cos x)^(2))]=(-2)/((1+ cos x))`
`"Now, "2e^(-y//2)=2cdote^(-("In "(1+cos x)^(2))/(2))=(2)/((1+cos x))`
`therefore" "(d^(2)y)/(dx^(2))+(2)/(e^(y//2))=0`