Question

Let F(x)=3x^2+4, Evaluate

http://webwork.math.ttu.edu/wwtmp/equations/aa/06edce2ad5d4d16acfabe85fd1acfb1.png

Answer 1

That's a messy one...\[\lim_{h \rightarrow 0} \frac {f(h-1) - f(-1)}{h}\]

Answer 2

sure is!

Answer 3

\[\lim_{h \rightarrow 0} \frac {3(h-1)^2 + 4 - 7}{h}\]

Answer 4

-6

Answer 5

Dang! good answer Ackhat but how?

Answer 6

\[\lim_{h \rightarrow 0} \frac {3h^2 - 6h}{h}\]

Answer 7

\[\lim_{h \rightarrow 0} \frac {h(3h - 6)}{h} = \lim_{h \rightarrow 0} 3h - 6 \]

Answer 8

plug in 0 for h, and you get the limit to be -6.

Answer 9

thanks everyone!

Answer 10

Rogue on your second post how did you get -7 on the end of the numerator?

Answer 11

f(-1), plug in -1 into F(x)=3x^2+4

Answer 12

but doesn't that just make 1 because -1 multiplied by 3 will result in -3 plus 4 is going to be 1 right?

Answer 13

I keep getting 7 + 7 at the end rather than them canceling out

Answer 14

f(-1) does equal +7, but in the limit formula, you are subtracting the +7.

Answer 15

well how does 3(-1)+4 equal positive seven if your not using that subtraction sign to change the now negative 3 into a positive 3 to make seven? dosnt the subtraction sign change in this process?

Answer 16

keeping the 2 from canceling?

Answer 17

:3 Your reading the function wrong. Its (-1)^2.

Answer 18

so it is thanks again man your a life saver!

Answer 19

Hehe, no problem =)