GOING TO BED. WHEN I WAKE UP NEXT MORNING I'M GOING TO PAY FIRST PERSON WHO POSTS CORRECT ANSWER + WORK! 

 

thanks 

Edited October 16, 201510 yr by Master Chief

what year of school is this?

what year of school is this?

senior 

calc

This might be completely wrong but this is how I would of approached the problem

So I used P = Population and "." as being a multiplication and ^ as to the power of.

An exponential function is usually defined as
P = a.b^t
If t = 0 at 1990 then at 1993, t = 3 and at 2005, t = 15

Therefore we can make the two equations

For P(1993) -->     a.b^3 = 255
and P(2005) -->    a.b^15 = 212 

If we solve these simultaneously because we have two variables, then we arrive at the answers
 

a = 267.0491871 and b = 0.9847280448

Using these values you can then put into a graph and create your exponential function by graphing this

P = 267.0491871 x 0.9847280448^t

http://i.imgur.com/Q64LuSq.png

 

Edited October 16, 201510 yr by dank vitamins

So this is a decaying exponential. Therefore it'll take the format of P(t)=Ae^(bt), where t represents years, A represents initial population at 1990, and b is the decaying factor. 

 

Some rules to be familiar with. The inverse of an exponential 'e' is ln, the natural logarithm. Others is dividing by exponents, you take away the power. Just google if you're unsure. 

 

Edited October 16, 201510 yr by Caesar

Shouldn't you need to work this out yourself ? may be in a test or somthing?
 

So this is a decaying exponential. Therefore it'll take the format of P(t)=Ae^(bt), where t represents years, A represents initial population at 1990, and b is the decaying factor. 

 

Some rules to be familiar with. The inverse of an exponential 'e' is ln, the natural logarithm. Others is dividing by exponents, you take away the power. Just google if you're unsure.

Interesting approach, might be what hes looking for 

I live in Australia so my approach was much different

Interesting approach, might be what hes looking for 

I live in Australia so my approach was much different

I live in Australia aswell mate :P I remember doing this is high school. Both methods are correct, except it's much easier to work out using euler's number, since you can isolate the decaying factor easier by using LN().

To double check my method, use the final formula provided. Substitute in b = 3, and b = 15, you should get 255, and 212

Shouldn't you need to work this out yourself ? may be in a test or somthing?

 

 

 

He won't have to worry about it on any upcoming test. If they make it extra credit they don't expect you to know how to do it, they just give you bonus points if you do. And they can't put things they don't expect you to already know on a test.

He won't have to worry about it on any upcoming test. If they make it extra credit they don't expect you to know how to do it, they just give you bonus points if you do. And they can't put things they don't expect you to already know on a test.

oh okay i don't know how the american system works im guessing its american 

So this is a decaying exponential. Therefore it'll take the format of P(t)=Ae^(bt), where t represents years, A represents initial population at 1990, and b is the decaying factor. 

 

Some rules to be familiar with. The inverse of an exponential 'e' is ln, the natural logarithm. Others is dividing by exponents, you take away the power. Just google if you're unsure. 

 

 

 

This might be completely wrong but this is how I would of approached the problem

So I used P = Population and "." as being a multiplication and ^ as to the power of.

An exponential function is usually defined as

P = a.b^t

If t = 0 at 1990 then at 1993, t = 3 and at 2005, t = 15

Therefore we can make the two equations

For P(1993) -->     a.b^3 = 255

and P(2005) -->    a.b^15 = 212 

If we solve these simultaneously because we have two variables, then we arrive at the answers

 

a = 267.0491871 and b = 0.9847280448

Using these values you can then put into a graph and create your exponential function by graphing this

P = 267.0491871 x 0.9847280448^t

http://i.imgur.com/Q64LuSq.png

tyvm. Are these both right answers? Just worded differently?

Funny how this is coming from an ex mod and it's not even allowed.

And then it's not even in the right section.

And then he's only paying $3.

Come on, OP.

tyvm. Are these both right answers? Just worded differently?

Use Caesar's solution. His answer is a natural exponential function and looks better.

 

However, I would round off the values to 3 numbers, since there are max 3 digits in the question, if you understand what I mean.

Edited October 16, 201510 yr by Woody

Use Caesar's solution. His answer is a natural exponential function and looks better.

 

However, I would round off the values to 3 numbers, since there are max 3 digits in the question, if you understand what I mean.

yeah I would use his too haha!

Funny how this is coming from an ex mod and it's not even allowed.

And then it's not even in the right section.

And then he's only paying $3.

Come on, OP.

wait so what against the rules?

asking for help with homework?

yeah I would use his too haha!

wait so what against the rules?

asking for help with homework?

Pretty sure paying someone for homework is.

Or was it just offering to do homework. Hmm