• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

more limiting sum questions!!! (1 Viewer)

atakach99

Member
Joined
May 19, 2007
Messages
146
Gender
Male
HSC
2008
A frog jumps 0.5m. It then jumps 0.1m and on each subsequent jump travels 0.2m of the previous distance. Find the total distance through which the frog jumps.

I need help setting this question out
can somebody plz explain how to use limiting sum formula to find answer.
thks
 

vds700

Member
Joined
Nov 9, 2007
Messages
861
Location
Sydney
Gender
Male
HSC
2008
atakach99 said:
A frog jumps 0.5m. It then jumps 0.1m and on each subsequent jump travels 0.2m of the previous distance. Find the total distance through which the frog jumps.

I need help setting this question out
can somebody plz explain how to use limiting sum formula to find answer.
thks
d = 0.5 + 0.5(1/5) + 0.5(1/5)^2 + 0.5(1/5)^3 +...
a = 0.5, r = (1/5)
limiting sum = a/(1-r)
= 0.5/(4/5) = 0.625 m
 

munchiecrunchie

Super Member
Joined
Apr 2, 2007
Messages
432
Gender
Female
HSC
2008
GP, a = 0.5, r = 0.2

since -1 < r < 1 , there is a limiting sum

limiting sum = a / 1 -r
= 0.5 / 0.8
= 0.625 m
 

lydia1992

scientificfield
Joined
Oct 7, 2011
Messages
52
Location
australia
Gender
Female
HSC
2012
Uni Grad
2016
what about the 0.1 .. the question says it then jumps 0.1 m ??????????
 

qwerty44

Member
Joined
Oct 12, 2011
Messages
557
Gender
Male
HSC
2013
d = 0.5 + 0.5(1/5) + 0.5(1/5)^2 + 0.5(1/5)^3 +...
a = 0.5, r = (1/5)
limiting sum = a/(1-r)
= 0.5/(4/5) = 0.625 m
Wouldn't you have to multiply it by two because your solution only accounts for the jumping up, but not when the frog comes down after reaching its height?

So while the first jump was 0.5m high, the frog essentially jumped a total of 1m. So the final answer would be 0.625 x 2=1.25m

The total distance in which the frog travelled is 1.25m
 
Last edited:

RealiseNothing

what is that?It is Cowpea
Joined
Jul 10, 2011
Messages
4,591
Location
Sydney
Gender
Male
HSC
2013
Wouldn't you have to multiply it by two because your solution only accounts for the jumping up, but not when the frog comes down after reaching its height?

So while the first jump was 0.5m high, the frog essentially jumped a total of 1m. So the final answer would be 0.625 x 2=1.25m

The total distance in which the frog travelled is 1.25m
It's 0.625, the distance is along the ground, not in the air.
 

qwerty44

Member
Joined
Oct 12, 2011
Messages
557
Gender
Male
HSC
2013
It's 0.625, the distance is along the ground, not in the air.
Well it says, the distance through which the frog travelled. It didn't travel through 0.625m along the ground, it travelled through 1.25m of air. I no it sounds stupid but i got a similar question with a ball bouncing.

EDIT: It depends whether the question meant he jumps 0.5m high or across. OP is that the full question? Also what is the answer?
 
Last edited:

RealiseNothing

what is that?It is Cowpea
Joined
Jul 10, 2011
Messages
4,591
Location
Sydney
Gender
Male
HSC
2013
Well it says, the distance through which the frog travelled. It didn't travel through 0.625m along the ground, it travelled through 1.25m of air. I no it sounds stupid but i got a similar question with a ball bouncing.

EDIT: It depends whether the question meant he jumps 0.5m high or across. OP is that the full question? Also what is the answer?
It's across, hence it's 0.625.
 

SpiralFlex

Well-Known Member
Joined
Dec 18, 2010
Messages
6,960
Gender
Female
HSC
N/A
*Points to date of the original post*

From memory this question is from the MIF book. Yes 0.625 is the answer.
 

CM_Tutor

Moderator
Moderator
Joined
Mar 11, 2004
Messages
2,642
Gender
Male
HSC
N/A
@Lemon01, are you unclear on the answers provided above? Is there something that we could clarify?
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top