Question

Please help! MEDAL GIVEN!
-A human embryo starts at a weight of 0.0125 milligrams. The weight increases exponentially at about 28.5% each day.
a. write an exponential equation to model this situation
b. Define the variables in your equation, include units
c. Use your equation to predict the weight of the embryo after 7 days. Show the steps
d. Use your equation and the guess and check method, predict when the embryo will be twice its initial weight. Give your answer to the nearest hour.

Answer 1

HI :D

Answer 2

hello haha :-)

Answer 3

HI again XD

Answer 4

You have to use this if I'm not mistaken:
\[\LARGE y=a(1+r)^2\]

a = initial amount before measuring growth/decay
r = growth/decay rate (often a percent)
x = number of time intervals that have passed

Answer 5

yes :)

Answer 6

Whoops, that should be an "x" not a 2

Answer 7

x determines the time

Answer 8

So can you come up with the equation based on that?

Answer 9

y=0.0125(1+0.285) ^x @Luigi0210

Answer 10

Right! Now you could do the rest pretty easily :)

Answer 11

so we solved for a already haha

Answer 12

for b how would i define the variables

Answer 13

When I gave you the standard equation, I told you what each variable meant, use that.

Answer 14

oh ok! :) thanks so much for c it's asking for 7 days so i just plug 7 days into x

Answer 15

i'm just not sure how to do d

Answer 16

For c, yes. And for D, take the initial weight, double it, and set it equal to the equation and solve.
\[\LARGE 0.25=0.0125(1+0.285)^x\]

Answer 17

oh ok :) here I believe we use logs… to estimate the value of x

Answer 18

That's actually the EXACT way to find it.. the guess and check way is to just plug in random values and see which gives you one closest to 0.25

Answer 19

so here we would actually divide by 0.0125 both sides of the equal sign.. how would we plug in for logs?

Answer 20

When the log part comes use this!