The derivative of a function f is given by f′(x)=ln∣x∣⋅x.On which interval is the graph of f concave up?Use a graphing calculator.Choose 1 answer:(A) −1<x<0="" and="" =""x="">1(B) x>0 (C) x<0 (D) x<-0.368 and x>0.368 (E) All real numbers
Q. The derivative of a function f is given by f′(x)=ln∣x∣⋅x.On which interval is the graph of f concave up?Use a graphing calculator.Choose 1 answer:(A) −1<x<0 and x>1(B) x>0(C) x<0(D) x<−0.368 and x>0.368(E) All real numbers
Calculate First Derivative: To determine where the graph of f is concave up, we need to find the second derivative, f′′(x), and look for where it is positive.f′(x)=ln∣x∣⋅xf′′(x)=dxd(ln∣x∣⋅x)
Apply Product Rule: Use the product rule for differentiation: uv' = u'v + uv'. Let u=ln∣x∣ and v=x. Then u′=x1 and v′=1. f′′(x)=(x1)x+ln∣x∣⋅1
Simplify Second Derivative: Simplify the second derivative: f′′(x)=1+ln∣x∣
Determine Positive Values: Find where f′′(x) is positive: 1 + \ln|x| > 0 \ln|x| > -1
Solve for x (x > 0): Solve for x in the inequality \ln|x| > -1. For x > 0: \ln(x) > -1 For x < 0: \ln(-x) > -1
Solve for x x < 0: Exponentiate both sides of the inequalities to solve for x.For x > 0: e^{\ln(x)} > e^{-1}, so x > \frac{1}{e}For x < 0: e^{\ln(-x)} > e^{-1}, so -x > \frac{1}{e}, which means x < -\frac{1}{e}
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