A Parabola Meets an Exponential

7/10functionscalculusMonotonicityCasework

Problem

Let f(x)=m(x2m)(x+m+1)f(x) = m(x - 2m)(x + m + 1) and g(x)=ex1g(x) = e^x - 1. Determine, with proof, which of the following are true:

1. when m=1m = 1, the equation f(x)=g(x)f(x) = g(x) has exactly one real solution; 2. when m(1,0)m \in (-1, 0): for every xRx \in \mathbb{R}, f(x)<0f(x) < 0 or g(x)<0g(x) < 0; 3. when m(0,1)m \in (0, 1): for every x(,2)x \in (-\infty, -2), f(x)g(x)<0f(x)g(x) < 0; 4. there exists mRm \in \mathbb{R} such that f(x)g(x)<0f(x) - g(x) < 0 for every xRx \in \mathbb{R}.

Answer

Solution

Difficulty7/10
Topicsfunctions, calculus, Monotonicity, Casework

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