Question

Why don't I have to factor out the (1+h)^2? on problem 2, page 2?

http://www.math.wisc.edu/~hernande/Teaching/UM/Math115Sec011Winter2011/Quizzes/Quiz3/Solution/Quiz3Sol.pdf

Answer 1

yea but i don't need to square 1+h because why? lol

Answer 2

usually i have to square it... that's why. especially for a slope problem.

Answer 3

I don't understand the question. you are asked to find the average velocity = distance/time

the distance traveled in the time between 1 and 1+h (with h=0.1) is
4(1.1)^2 +3 - ( 4*1^2 +3)
4*1.21 + 3 -4 -3
4.84 -4
0.84
the time interval is 0.1 sec, so velocity is 0.84/0.1 = 8.4 sec

Answer 4

in other words, you do square (1+h)

Answer 5

but when i squared (1+h), the 4's and 3's cancel. i get 8.04 when the answer should be 8.4 m/s

Answer 6

in each case, you find how far the particle got by time step 1. Then find where it is at time step 1+h. The difference between those two distances is how far it moved in h secs.

Answer 7

but when i squared (1+h), the 4's and 3's cancel. i get 8.04 when the answer should be 8.4 m/s

for case (i), with h = 0.1 1+h is 1.1
1.1*1.1= 1.21
4*1.21= 4.84
subtract 4
0.84
divide by 0.1 to get 8.4

you must have made a mistake doing 1.1 * 1.1 ??

Answer 8

I am not sure how you did your calculation, but you have a "bug" in it, so it would be good to figure out where you are going wrong...

Answer 9

\[4(h ^{2}+2h+1) +3-4(1)^{2}-3\] since t =1?

Answer 10

and t = 1+h

Answer 11

yes. that looks ok. then
4h^2 +8h +4 +3 -4 -3 = 4h^2+8h
if we divide by h (to get velocity)
4h+8

with h=0.1 this is 4*0.1+8 = 0.4+8= 8.4 perfect!

Answer 12

ok that's where i went wrong. i factored out 4h so it would be 4h ( h^2 +2) and canceled out the h's so it would be left with 4(h^2+2)

Answer 13

if you factor out 4h, it should be 4h(h+2) and 4(h+2) after dividing by h

Answer 14

yea that's my mistake... i left the squared. thanks :)

Answer 15

i can't believe it was that miniscule

Answer 16

so close....

Answer 17

i know! such a tiny mistake could cost me an answer by one decimal place -_-

Answer 18

sometimes it just doesn't work out...good luck!