Master Chief Posted October 16, 2015 Posted October 16, 2015 (edited) 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, 2015 by Master Chief 1
Master Chief Posted October 16, 2015 Author Posted October 16, 2015 what year of school is this? senior calc
Jesus1 Posted October 16, 2015 Posted October 16, 2015 (edited) 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 asP = a.b^tIf t = 0 at 1990 then at 1993, t = 3 and at 2005, t = 15Therefore we can make the two equationsFor P(1993) --> a.b^3 = 255and 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 = 0.9847280448Using these values you can then put into a graph and create your exponential function by graphing thisP = 267.0491871 x 0.9847280448^t http://i.imgur.com/Q64LuSq.png Edited October 16, 2015 by dank vitamins 1
Caesar Posted October 16, 2015 Posted October 16, 2015 (edited) 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, 2015 by Caesar 3
4nr Posted October 16, 2015 Posted October 16, 2015 Shouldn't you need to work this out yourself ? may be in a test or somthing?
Jesus1 Posted October 16, 2015 Posted October 16, 2015 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
Caesar Posted October 16, 2015 Posted October 16, 2015 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 1
Paradox68 Posted October 16, 2015 Posted October 16, 2015 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.
4nr Posted October 16, 2015 Posted October 16, 2015 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
Master Chief Posted October 16, 2015 Author Posted October 16, 2015 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?
RoomScape Posted October 16, 2015 Posted October 16, 2015 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.
Woody Posted October 16, 2015 Posted October 16, 2015 (edited) 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, 2015 by Woody 1
Jesus1 Posted October 16, 2015 Posted October 16, 2015 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?
RoomScape Posted October 16, 2015 Posted October 16, 2015 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
