Mark M. answered 08/03/19
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
f(x) = (5ex - 5e-x) / 2
f'(x) = (5ex + 5e-x) / 2 > 0 for all x.
So, f(x) is increasing on (-∞, ∞)
Therefore, there are no relative extrema.
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f"(x) = (5ex - 5e-x) / 2
f"(x) = 0 when 5ex = 5e-x
e2x = 1
2x = 0
So, x = 0
When x < 0, f"(x) < 0. So, f(x) is concave down.
When x > 0, f"(x) > 0, So, f(x) is concave up
Inflection point: (0, f(0)) = (0, 0)