Q. Let f(x)=xex+exx+1 when x=−1.f is continuous for all real numbers.Find f(−1).Choose 1 answer:(A) 1(B) e(C) 2
Check Function Continuity: To find the value of f(−1), we need to determine if the function f(x) has a removable discontinuity at x=−1. If it does, we can find the limit of f(x) as x approaches −1 to find f(−1).
Plug in x=−1: First, let's plug in x=−1 into the function to see if it is defined at that point.f(−1)=(−1+1)/((−1)e−1+e−1)f(−1)=0/((−1)/e+1/e)f(−1)=0/((−1+1)/e)f(−1)=0/0This is an indeterminate form, which means the function is not defined at x=−1, and there is a discontinuity at that point.
Apply L'Hôpital's Rule: Since f(x) is continuous for all real numbers and there is a discontinuity at x=−1, it must be a removable discontinuity. To find the value of f(−1), we need to calculate the limit of f(x) as x approaches −1.
Calculate Limit: We can use L'Hôpital's Rule to evaluate the limit since we have an indeterminate form of 0/0. We will differentiate the numerator and the denominator separately.The derivative of the numerator with respect to x is:dxd(x+1)=1The derivative of the denominator with respect to x is:dxd(xex+ex)=ex+xex+ex=2ex+xex
Final Value of f(−1): Now we apply L'Hôpital's Rule by taking the limit of the derivatives as x approaches −1: limx→−1ex+xex+ex1 Plugging in x=−1, we get: lim=e−1+(−1)e−1+e−11 lim=(e1)−(e1)+(e1)1 lim=e11 lim=e
Final Value of f(−1): Now we apply L'Hôpital's Rule by taking the limit of the derivatives as x approaches −1: limx→−1ex+xex+ex1 Plugging in x=−1, we get: lim=e−1+(−1)e−1+e−11 lim=(e1)−(e1)+(e1)1 lim=e11 lim=eTherefore, the value of f(−1) is x0, which means the correct answer is (B) x0.
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