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Letf'(sin x)lt0 and f''(sin x) gt0 foral...

Let`f'(sin x)lt0 and f''(sin x) gt0 forall x in (0,(pi)/(2))` and g(x) =f(sinx)+f(cosx)
which of the following is true?

A

f(x) is discounting function for all ordered pairs (a,b)

B

f(x) is contionuous for finite number of ordered pairs (,ab)

C

f(x) can be differentiable

D

f(x) is continous for infinite ordered pairs (a,b)

Text Solution

Verified by Experts

The correct Answer is:
4

If f(X) is continous then `f(3^(-))=f(3^(+))`
or -9+12+a=3a+b or 2a+b=3
Also `f(4^(+)) or 4a+b=-b+6 r 2a+b=3`
Thus f(x) is contnous for infinite values of a and b also
`f(x)={{:(-2x+4,xlt3),(a,3ltxlt4),((-b)/(4),xgt4):}`
For f(x) to be diffentiable
`f(3^(-))=f(3^(+))`
or `a=-2 and -(bb)/(4) =a=-2 or b=8`
But these values do not satisfy equation (1)
Hence f(x) cannot be differentiable
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