A) 2
B) 0
C) 3
D) 4
Correct Answer: C
Solution :
[c] For A.P \[2.f(x)=({{2}^{1-x}}+{{2}^{1+x}})+({{3}^{x}}+{{3}^{-x}})\] \[\Rightarrow f(x)={{2}^{x}}+{{2}^{-x}}+\frac{{{3}^{x}}+{{3}^{-x}}}{2}\] By AM-GM inequality \[{{2}^{x}}+{{2}^{-x}}\ge 2\] and \[{{3}^{x}}+{{3}^{-x}}\ge 2\] at x = 0 \[\therefore f(x)\ge 2+1\] \[f(x)\ge 3\]You need to login to perform this action.
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