1.

If `lim_(xrarr oo) (1+(a)/(x)+(b)/(x^2))^(2x)=e^2`, thenA. `a=1,b=2`B. `a=2,b=1`C. `a=1,b in R`D. `a=b=1`

Answer» Correct Answer - C
We have,
`lim_(xto oo) (1+(a)/(x)+(b)/(x^2))^2x`
`=e^(x^(lim_(x to oo)((a)/(x)+(b)/(2))xx2x))=e^xlim_(xto oo)(2a+(2b)/(x))=e^2a`
`lim_(xto oo) (1+(a)/(x)+(b)/(x^2))^2x=e^2rArr e^2 rArr e^2a= e^2 rArr 2 rArr a=1`.
Hence, `a=1 and b in R`.


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