1.

Show that the equation `e^(sinx)-e^(-sinx)-4=0`has no real solution.A. infinite number of real rootsB. no real rootsC. exactly one real rootD. exactly four real roots

Answer» Correct Answer - 2
Let ` e^(sin x) =t`
` rArr t^(3) - 4t - 1 = 0 `
` t = (4 pmsqrt(16 + 4))/(2)`
`rArr t = e^(sin x ) = 2 pm sqrt(5)`
`rArr t = e^(sin x ) = 2 - sqrt(5),e^(sin x ) = 2 + sqrt(5)`
`rArr e^(sin x) = - sqrt(5) lt 0 ` , whihc is not possible
or ` sin x = In (2 + sqrt(5)) gt 1`, which is not possible
Hence no solution .


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