College Algebra: reviewing for my final exam!!
The growth in the population of a biology experiment fits A(t)=445e^0.013t where t is the number of years since 1987. Estimate the population in the year 2000.
** I tried doing it myself, but I'm not getting the correct answer**

Question

College Algebra: reviewing for my final exam!!
The growth in the population of a biology experiment fits A(t)=445e^0.013t where t is the number of years since 1987. Estimate the population in the year 2000. 
** I tried doing it myself, but I'm not getting the correct answer**

p0sitr0n · Answer

you have to find t:  t=2000-1987=13
thus A(13)=445 e^(0.013*13) =~ 527

anonymous · Answer

I got 13, but how did you solve it @P0sitr0n  ? Step-by-step

anonymous · Answer

As far as I got on mine was
$$A(13)=445e ^{0.169}$$

p0sitr0n · Answer

i guess using a calculator is mandatory  for this lol

anonymous · Answer

I am only allowed to use a scientific calculator for the exam.

p0sitr0n · Answer

if you do not have e on your calculator, use e~ 2.718

anonymous · Answer

How about ln?

p0sitr0n · Answer

ln is the inverse function of e

anonymous · Answer

Okay, so what did you press on your calculator (in order) to get the answer?

p0sitr0n · Answer

$$e^x =y => \ln y =x$$

p0sitr0n · Answer

i have a button which is $$e^x$$

anonymous · Answer

Oh wait, I think I did it!

anonymous · Answer

I pressed 0.169, then e^x times 445 and got 526.6 which is 527

p0sitr0n · Answer

it may easier to memorize that $$e = \sum_{k=0}^{\infty} \frac{ 1 }{ k! } = \frac{ 1 }{ 1} +  \frac{ 1 }{ 1 \times 2} + \frac{ 1 }{ 1 \times 2 \times 3} + ..$$

p0sitr0n · Answer

yeah thats the thing

anonymous · Answer

Thank you very much P0sitr0n!! I'll definitely remember this for my exam on Tuesday!! :)

p0sitr0n · Answer

just forget the big sum above and use the e^x button  since you have it lol

anonymous · Answer

I will!! :)