# Math Help - instantaneous rate of change

1. ## instantaneous rate of change

Let
f(x)=5 ·x2+2 ·x−3 and let x0= 1.

The instantaneous rate of change of f at x= 1 equals ?

2. Originally Posted by samtheman17
Let
f(x)=5 ·x2+2 ·x−3 and let x0= 1.

The instantaneous rate of change of f at x= 1 equals ?
= the calculus section since differentiation is involved.

$f(x) = 5x^2 + 2x -3 =0$

We want to find $f'(1)$
$
f'(x) = 10x + 2$

$f'(1) = 10+2 = 12$

3. instantaneous rate of change is derivative

f'(x)=10x+2 now plug in x=1

4. Since this has been posted in the Pre-Calculus section, I doubt that the OP knows what a derivative is, or how to calculate it.

I would say at a Pre-Calculus level, it is enough to evaluate the difference quotient with a small change in $x$, say $0.01$.

$\frac{f(1.01) - f(1)}{1.01 - 1} =$?