maths task! :)
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22 Jun 2010, 09:57
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Journals
jo guys!
Today is the 22th juny, the longest day in the year!
From my memory the day ends like 22:27 and the next day begins at 04:41 (correct
me if im worng :))
I have a nice and at once easy maths task for u, hähä, so if ur interested, here it is:
a) Imagine, the Ball falls from the beginning height 2 meter on the ground. After it lands, it jumps again up, but now it reaches only 6/7 of the previous height. After that it falls again, jumps and reaches 6/7 from the previous height and so forth.
How long is the way, the ball does?
so post ur solution.
gg, i know the answer ;D (hopefully i solved it correctly myself)
btw, if u solved this try this extension:
b) how often does the ball have to jump, till the difference between the whole way and the distance it covered is maximal 1 Millimeter
Today is the 22th juny, the longest day in the year!
From my memory the day ends like 22:27 and the next day begins at 04:41 (correct
me if im worng :))
I have a nice and at once easy maths task for u, hähä, so if ur interested, here it is:
a) Imagine, the Ball falls from the beginning height 2 meter on the ground. After it lands, it jumps again up, but now it reaches only 6/7 of the previous height. After that it falls again, jumps and reaches 6/7 from the previous height and so forth.
How long is the way, the ball does?
so post ur solution.
gg, i know the answer ;D (hopefully i solved it correctly myself)
btw, if u solved this try this extension:
b) how often does the ball have to jump, till the difference between the whole way and the distance it covered is maximal 1 Millimeter
In my city.
if u dont want or have no time, dont do it
+ sunset according to my weather station is @ 21:37pm :~>
a=2
q=6/7
Sn=a/(1-q)=14meters
_______
an=0.001
an=a*q^n
an=2*(6/7^n)
2*6/7^n=0.001
6/7^n=0.001/2
log0.0005/log(6/7)=~50
C: 2*(6/7^50)=<0.001
so 50 times
a is wrong
b) is also right unless 1mm isnt 0.001m-after bouncing 50 times each next bounce is less then 1mm
geenius oled :)
maaan
no, it's June 22nd
2+2*sum((6/7)^i, i, 1, 200) = 14
<3 my calculator which I'm not allowed to use
I've an Texas Instruments voyage 200.
Way = 2+SUM [2*2*(6/7)^n]
in the sum n begins with 1.
so you are wrong :P
so 14*2 - 2(because it fell from 2m and didnt reach this lvl) = 26
and then sum*2-2
so 14*2-2=26?
aaaa blablabla im too lazy
b)
an=0,001
q=6/7
a1=2
an=a1*q^n-1
0,001= 2*(6/7)^(n-1)
0,0005=6/7^(n-1)
n-1=log 6/7 1/2000
n-1= log 1/2000 / log 6/7
n-1 = (log1 - log 1000*2)/ log6 - log7
n-1 = 0 -(3+log2)/(log6 - log7)
n = [-(3+log2)/(log6-log7)]+1
but i got no idea how to solve it w/o using calculator log6-log7<0 so n>0