Question

1) A bungee jumper plummets from a high bridge to the river below and then bounces back over and over again. At time t seconds after her jump, her height H (in meters) above the river is given by the function:

Answer 1

\[H(t) = 100+ 75e^{t/20}\cos((\pi/4)t) \]

Answer 2

Find her height at the times indicated in the table.

Answer 3

t: 0,1,2,4,6,8,12

Answer 4

i just plug in right?

Answer 5

yes just plugin

Answer 6

thank you

Answer 7

np :)
careful about cos ok
cos(0) = 1
cos(pi/4), cos(pi/2), cos(pi).... compute them first

Answer 8

cos(pi/4)=.53 aprox ?

Answer 9

cos(pi/4) = 1/sqrt(2)

Answer 10

H(1) = 41.74?

Answer 11

i just want to make sure to see if im doing it right

Answer 12

how did u get that, u should get more than 100 right

Answer 13

i meant 141.74

Answer 14

\(H(t) = 100+ 75e^{t/20}\cos((\pi/4)t) \)

put t= 1

\(H(1) = 100+ 75e^{1/20}\cos((\pi/4)1) \)

\(H(1) = 100+ 75e^{1/20}\frac{1}{\sqrt{2}}\)

http://www.wolframalpha.com/input/?i=100%2B+75e%5E%7B1%2F20%7D%5Cfrac%7B1%7D%7B%5Csqrt%7B2%7D%7D

Answer 15

H(1) = 155.75

Answer 16

did u get, H(0) = 175 ?

Answer 17

yes

Answer 18

good :) try the remaining values

Answer 19

H(2)= 117.38

Answer 20

No. when u put t = 2,

\(H(t) = 100+ 75e^{t/20}\cos((\pi/4)t) \)

\(H(t) = 100+ 75e^{2/20}\cos((\pi/4)2) \)

\(H(t) = 100+ 75e^{2/20}\cos(\pi/2) \)

Answer 21

wats cos (pi/2) ?

Answer 22

0

Answer 23

so it would be 100

Answer 24

yes !

Answer 25

and H(40 would be 8.5

Answer 26

(4)**

Answer 27

\(H(t) = 100+ 75e^{t/20}\cos((\pi/4)t) \)

put t=4

\(H(4) = 100+ 75e^{4/20}\cos((\pi/4)4) \)

\(H(4) = 100+ 75e^{1/5}\cos(\pi) \)

\(H(4) = 100+ 75e^{1/5}(-1) \)

http://www.wolframalpha.com/input/?i=100%2B+75e%5E%7B1%2F5%7D%28-1%29

Answer 28

yes you're right lol

8.39


~ 8.4

Answer 29

lol yay but now im confused... H(8) is coming out to 211.75

Answer 30

\(H(8) = 100+ 75e^{8/20}\cos((\pi/4)8)\)

\(H(8) = 100+ 75e^{8/20}\cos(2\pi)\)

\(H(8) = 100+ 75e^{8/20} 1 \)

http://www.wolframalpha.com/input/?i=100%2B+75e%5E%7B8%2F20%7D

Answer 31

wolfram says 211.89

Answer 32

and for H(12) i got -36.5 is that even posssible considering bungee jumping?

Answer 33

lol he must be sinking in waters and dead be now :o
let me think lol

Answer 34

haha lol

Answer 35

okay wat that means is, our equation will not work for t >= 12

cuz, height -36.5 makes no sense. let me see if i cna quickly plot it

Answer 36

have a look at attached graph,
after 10, the graph is becoming negative.

so if the equation equation is really a practical one, the jumper wud die for sure in waters ;)

Answer 37

hehe now we know more about bungee jumping :p

Answer 38

quick question : y=-3sin pi(x)
whats the amp and period?
amp= -3 ...and what would the period be ? 2?

Answer 39

ahh yes be better cry mayday before t = 12 lol

Answer 40

*he

Answer 41

haha :p

Answer 42

amp is distance from mean position.
it can never be negative ok

Answer 43

y = -3sin(pix)

amp = |-3| = +3

Answer 44

period is 2 correct !

Answer 45

oh ok :) but how would i graph the period 2