How do you find the instantaneous rate of change for $f(x) = x^2 + 3x$ at $x = 2$ ?

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Answer 1 · 2015-04-28T01:35:52

The "instantaneous rate of change" is another expression for the "slope" or "derivative#

Given $f(x) = x^2+3x$

$(d f(x))/(dx) = 2x+3$

At $x=2$
the instantaneous rate of change is
$2(2)+3 = 7$

How do you find the instantaneous rate of change for f(x) = x^2 + 3xf(x) = x^2 + 3x at x = 2x = 2?