00:01
In this question, we are asked to calculate the derivative of the function f using the definition of the derivative.
00:07
And first we need to calculate f of x plus h.
00:11
And to do that, we need to plug in x plus h for x in the formula for f, and we are going to get negative 3 times x plus h squared minus 4 times x plus h plus 2.
00:28
Now let's expand that expression.
00:30
We are going to get negative 3 times x squared plus 2 x h plus h squared minus 4 x minus 4 h plus 2 and this further simplifies to negative 3 x squared minus 6 x h minus 3h squared minus 4 x x minus 4 h plus 2 now we need to calculate the difference quotient f of x plus h minus f of x over h.
01:12
So what we are going to do is we will rewrite the expression we found in the previous step for f of x plus h.
01:30
And subtract f of x from that.
01:33
Recall that f of x is negative 3x squared minus 4x plus 2 divided by h.
01:47
Next we can cancel negative 3x squared, we can cancel negative 4x and we can cancel 2...