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Let f:[0,1] rarr R be a function.such thatf(0)=f(1)=0 and f''(x)+f(x) ge e^x for all x in [0,1].If the fucntion f(x)e^(-x) assumes its minimum in the interval [0,1] at x=1/4 which of the following is true ? |
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Answer» `f(x)lt 0 f (x) " for " 1/4 lt x lt 3/4` `phi(x) LE FOR0 ltx lt 1/4 and phi (x) gt 0" for " 1/4 lt x lt 1` `rArre^(-x)(f'(x) -f(x)) gt 0" for " lt x lt 1/4` and, `e^(-x)(f'(x) -f(x)) gt 0 for 1//4 lt x lt 1 ` `rArr f(x)lt f(x)for lt x lt 1/4 and f(x) gt f(x)for 1/4 lt x lt 1` Hence ,option (C ) is correct |
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