Math help please

Chamomile

Chamomile

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MBTI
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I have a math final tomorrow. I'm going over my notes and there is one problem I do NOT understand how to put into my graphing calculator. It involves exponential growth and decay.

Okay, so after putting all the garbage into the formula, I have:

y = 500e^(0.62123*6)

I'm positive the above is correct. However getting from this part to having the right answer on the calculator's screen is beyond me at the moment. I slept in that day. The answer is supposed to be 20,785, but I'm not getting that.

Can someone break this down as to how exactly it should be put into my calculator? Do I ignore the natural log? is it going towards the 500 or the exponent? So confuzzed :( Thanks
 
Chamomile said:
I have a math final tomorrow. I'm going over my notes and there is one problem I do NOT understand how to put into my graphing calculator. It involves exponential growth and decay.

Okay, so after putting all the garbage into the formula, I have:

y = 500e^(0.62123*6)

I'm positive the above is correct. However getting from this part to having the right answer on the calculator's screen is beyond me at the moment. I slept in that day. The answer is supposed to be 20,785, but I'm not getting that.

Can someone break this down as to how exactly it should be put into my calculator? Do I ignore the natural log? is it going towards the 500 or the exponent? So confuzzed :( Thanks
Click to expand...


what kind of calculator?

the order of operations is:

6*.62123
e^[answer of previous step]
500 * [answer of previous step]


Google calculator gives you 20785 if you copy & paste search it, so I agree that that's the correct one.
 
There is a program called "Microsoft Mathematics", it's free, and basically, like an advanced graphing calculator that shows steps in a problem and can create animated graphs based on it. Maybe it can help you.
 
Its a TI-84.

I'm getting a Syntax error when I attempt to take the natural log of an exponent
 
Peppermint said:
There is a program called "Microsoft Mathematics", it's free, and basically, like an advanced graphing calculator that shows steps in a problem and can create animated graphs based on it. Maybe it can help you.
Click to expand...

Thanks for the recommendation. I'm not seeing any DL's available for Macs so far, but I'll keep looking.
 
I hate syntax. You get one little thing wrong, and the whole thing doesn't work.
 
but... there is no natural log of an exponent in that expression? e is just a normal number, like pi, except it's somewhere around 2.71. You shouldn't be messing with the natural log at all. In text, the natural log looks like ln([stuff]), not e^([stuff])

If you're getting a syntax error, my first guess would be that you're typing "500e" without the * in there (it should be 500*e, but when we write things we often ignore the * between numbers and letters, because it's implied)

and my second guess would be that your parenthesis are mismatched somehow. Make sure you don't forget the ) when you type e^(0.62123*6)
 
This is the function you need:

exponentp.jpg


You need to hit the below button "2nd" near the screen, and then the "ln" button to access the e function.

It's the same as using the "Shift" button on your keyboard to get other symbols.
 
frozen_water said:
but... there is no natural log of an exponent in that expression? e is just a normal number, like pi, except it's somewhere around 2.71. You shouldn't be messing with the natural log at all. In text, the natural log looks like ln([stuff]), not e^([stuff])

If you're getting a syntax error, my first guess would be that you're typing "500e" without the * in there (it should be 500*e, but when we write things we often ignore the * between numbers and letters, because it's implied)

and my second guess would be that your parenthesis are mismatched somehow. Make sure you don't forget the ) when you type e^(0.62123*6)
Click to expand...

Thanks! I figured out this was my problem at about 4am haha. It was really confusing for me because my math professor will use 'e' interchangeably with 'ln' and mix them up sometimes (plus I missed the day when she went over how to input that equation). Luckily I just took the final and I'm pretty confident I passed, so woo!
 
Chamomile said:
Its a TI-84.

I'm getting a Syntax error when I attempt to take the natural log of an exponent
Click to expand...

Hmm, I'm getting the correct answer on my TI-84. You might want to try updating the firmware on your calculator. That might fix the problem, assuming you don't have the most recent firmware. However, since you said you work on a mac, you might have some problems... might not. I can't say for certain.
 
It was really confusing for me because my math professor will use 'e' interchangeably with 'ln' and mix them up sometimes
Click to expand...
That's very bizarre. Either your professor is making huge mistakes or you are misinterpreting what he has written down.

The natural logarithm of a variable x is simply the power to which one has to raise the number e in order to obtain the variable x. That is, If ln(x) = m, then e^m = x. e^x and ln(x) are not the same thing; indeed, ln(e^x) = e^(ln(x)) = x, so one could say they cancel each other out.
 
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