compound interest solve for r/t

[mazzzzz]

Hey guys.. I have been trying to solve the equation: A=P(1+R/N)[sup:1cqv2jog]NT[/sup:1cqv2jog]
for r for hours! To be honost, I have no clue how to do it...

If anyone here could help me try and solve the equation for r (I also need to solve it for t, which im not looking foward to), I would be very greatful,
Thanks,
Mazzzzz

 

[mmm4444bot]

... I have been trying ... for hours! To be honost [sic] ...

Hello Mazzzzzzzzzzzzzzzzz:

I hardly believe that you tried for hours to solve this exercise.

Have you taken any courses in algebra?

You really need those types of skills to solve equations.

Are you familiar with properties of exponents?

You really need those types of skills, too, for this exercise.

I have no idea where to start helping you because you have not shown any work at all, so I must guess.

Can you solve the given equation for A/P, followed by raising both sides to the power of 1/(NT)?

What can you do after investing "hours" of your time? (This is a rhetorical question.)

Cheers,

~ Howard I. Noe

PS: Please, read the post titled "Read Before Posting", if you have not already done so.

 

[mazzzzz]

I don't no how to solve for an exponent or a number withen perenthesis [()]...

Sense I don't know how, I've been shooting in the dark (also meaning I have no work on these two variables).
If you need any different informaiton, just ask...
Mazzzzz

P.S. I did read the post

 

[Denis]

Are you too busy or tired to look up exponent laws?

If a^x = b, then x = log(b) / log(a)

If a^x = b, then a = b^(1/x)

If that's not enough, you need classroom help.

 

[mazzzzz]

Thanks for the exponent laws..
I was able to figure out how to get r ( (((A/P)^(1/N))^(1/T)-1)N ), and now im working on t..

I tried these steps, but they don't work out in the end..

1. A=P(1+R/N)[sup:1ulodr38]nt[/sup:1ulodr38]
2. A^(1/T)=P(1+R/N)[sup:1ulodr38]n[/sup:1ulodr38]
3. 1/T=log(P(1+R/N)[sup:1ulodr38]n[/sup:1ulodr38])/log(A)
4. T=1(log(P(1+R/N)[sup:1ulodr38]n[/sup:1ulodr38])/log(A))

I can't get the above to work though,
Thnks n dvnc,
Mazzzzz

 

[stapel]

I don't no how to solve for an exponent or a number withen perenthesis [()]...

Goodness! Your instructor and your textbook certainly have skipped over a lot of material! (You state that you aren't familiar with how to work with parentheses or exponents, or how to solve exponential equations in particular. The gap between simplifying with parentheses and learning how to solve simple linear equations, and then working with exponentials and logarithms is usually many months! :shock: )

Unfortunately, it is not reasonably feasible to attempt here to replace the missing hours of classroom instruction or chapters in your text. Fortunately, there are loads of great lessons available online. But it would help if you could narrow down how far you've gotten, so we have a little better idea of the "gap" that you've been asked by your instructor to "jump". :wink:

For instance, have you worked with negative numbers at all? Are you familiar with how to "combine like terms"? Have you solved any sorts of equations at all (linear, quadratic, radical, etc)? Is your instructor expecting you to work with logarithms? And so forth. :?:

Thank you!

Eliz.

 

[mazzzzz]

When I said I didn't know I really meant I don't remember..

I've been working on a new program that uses compound interest, and I need to solve for each variable (except n).. I couldn't find any help online, so I came here to post the problem..
I was hoping you could refresh my memory on solving for a variable.
The equation in my last post was suppost to give you t[time].
So basicly, if you could tell me what I did wrong, it would be very helpful,
Thanks,
Mazzzzz

 

[Deleted member 4993]

Thanks for the exponent laws..
I was able to figure out how to get r ( (((A/P)^(1/N))^(1/T)-1)N ), and now im working on t..

I tried these steps, but they don't work out in the end..

1. A=P(1+R/n)[sup:h28925xn]nt[/sup:h28925xn]
2. A^(1/T)=P(1+R/n)[sup:h28925xn]n[/sup:h28925xn]
3. 1/T= n * log{P(1+R/n)}/log(A)

T = log(A)/[n * log{P(1+R/n)}]

4. T=1(log(P(1+R/N)[sup:h28925xn]n[/sup:h28925xn])/log(A))

I can't get the above to work though,
Thnks n dvnc,
Mazzzzz

 

[mmm4444bot]

When I said I didn't know I really meant I don't remember ...

When people do not say what they mean, communication fails.

-

... I was hoping you could refresh my memory on solving for a variable ...

I'm not sure who you are, what you are doing, or what you need.

This web site is primarily for helping students with homework assignments.

If you are out of school and working on some personal project, then you need to explain this situation up-front because we do not provide lessons to refresh people's memories over what they have forgotten from school. In fact, we do not, in general, provide any lessons at all on these bulletin boards.

Also, I have to be frank with you; when I read your posts, I think of somebody in the seventh grade.

Either you are trying to learn something or you just want somebody to give you solutions. Which is it?

If you tell me that you are out-of-school and that you just need the solutions in order to use some "program", then I will type the solutions for you.

If you tell me that you are trying to figure something out on your own because you are engaged in a process of learning, then you need to do it my way. My way is to follow the guidelines stated in the post titled "Read Before Posting".

-

r ( (((A/P)^(1/N))^(1/T)-1)N )

You did not type the equal sign, but the expression for r looks okay. Unless you have a reason for separating the exponents 1/N and 1/T, this expression can be simplied.

r = ( [A/P]^[1/(NT)] - 1 ) * N

Some people prefer to distribute the factor of N.

r = N * (A/P)^(1/[NT]) - N

(Of course, in all of these versions, the expression A/P must be greater than zero.)

-

2. A^(1/T) = P(1 + R/N)[sup:2qssbfqr]n[/sup:2qssbfqr]

Let's not interchange upper- and lower-case letters to represent the same value. In mathematics, the symbol N is not the same as the symbol n.

The mistake that you made in line (2) is that you only raised one of the factors on the right-hand side of the equation to the power of 1/T.

There are two factors on the right-hand side. (1 + R/N)[sup:2qssbfqr]NT[/sup:2qssbfqr] is one of these factors; P is the other.

When raising a product of factors to some power, each factor needs to be exponeniated.

Here's the symbolic representation of this particular rule of exponentiation.

(AB)[sup:2qssbfqr]c[/sup:2qssbfqr] = A[sup:2qssbfqr]c[/sup:2qssbfqr] * B[sup:2qssbfqr]c[/sup:2qssbfqr]

Cheers,

~ Mark

 

[mazzzzz]

Well, really I just need to figure out the equation.. Yes, I am out of school, and the only reason I had capitalized one n and left the other one lowercase is because I was representing the powers..

Also, if there is a way to find n, I would appreciate it.
Thanks for simplifing the first equation.

Thanks,
Mazzzzz

 

[mmm4444bot]

... Well, really I just need [the equations] ...

Thank you for stating your motivation.


\(\displaystyle R \;=\; N \cdot \left ( \frac{A}{P} \right )^{\frac{1}{N \cdot T}} -\; N\)


\(\displaystyle T \;=\; \frac{1}{N} \cdot ln\left ( \frac{A}{P} \right ) \cdot ln\left ( \frac{R + N}{N} \right )^{-1}\)

OR, expressed another way,

\(\displaystyle T \;=\; \frac{ln\left( \frac{A}{P} \right)}{N \cdot ln\left( \frac{R + N}{N} \right) }\)


I do not believe that the equation can be symbolically solved for N.

-

... the only reason I had capitalized one n and left the other one lowercase is because I was representing the powers ...

Are you sure that this is the only reason? You did not use lower-case letters to denote exponents in your original post. You used the superscript command to denote exponents; that is good enough.

Regardless, the number N is the same number whether it appears as an exponent or not. It is confusing to use different symbols to represent the same number.

If you use different symbols to represent the same number in your "program", then your "machine" may not treat them all as the same number.

Cheers,

~ Mark

 

[Denis]

I tried these steps, but they don't work out in the end..
1. A=P(1+R/N)[sup:5ty184mf]nt[/sup:5ty184mf]
2. A^(1/T)=P(1+R/N)[sup:5ty184mf]n[/sup:5ty184mf]
3. 1/T=log(P(1+R/N)[sup:5ty184mf]n[/sup:5ty184mf])/log(A)
4. T=1(log(P(1+R/N)[sup:5ty184mf]n[/sup:5ty184mf])/log(A))

You're complicating it!
Start this way:
(1 + R/N)^(NT) = A/P
Then:
NT = log(A/P) / log(1 + R/N)
T = [log(A/P) / log(1 + R/N)] / N

That's all she wrote!

> Also, if there is a way to find n, I would appreciate it.
There is no direct way; a process called "iteration" is required. Look it up!

EDIT: hey Mark, me no see yer post...yours "looks" better :wink: