1.

Leg `f(x)=x^3+a x^2+b x+5sin^2x`be an increasing function on the set `Rdot`Then find the condition on `aa n dbdot`A. `a^2-3b-15 gt 0`B. `a^2-3b+15 gt 0 `C. `a^2-3b+15 lt 0 `D. `a gt 0 and b lt 0 `

Answer» Correct Answer - C
`f(x)=x^3+ax^2+bx + 5 sin ^2x` increasing on R
`rArr (x) lt for all in R`
`rArr 3x^2a + (b-5)gt 0 for all x in R`
`rArr 3x^2+2ax(b-5) lt 0 rArr a^2-3b+15 lt 0 `


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