Question

how do you find the missing t in compond interest with the formula A=pert?

Answer 1

Use logarithms

Answer 2

If A=82000
P= 64054
r=7.6%
how do i get t?

Answer 3

post the formula

Answer 4

I will show you how to solve for t

Answer 5

\[A=Pe ^{rt}\]

Answer 6

A=Pe^(rt)
to solve
82000 = 64054^(.076t)
ln(8200) = (0.076t)ln(64054)
by the rule ln(x^(y)) = yln(x)
ln(8200)/ln(64054)(0.076) = t

Answer 7

the answer I got was 0.09729

Answer 8

Alternatively you could also do the following
82000 = 64054^(.076t)
log_(64054)8200=(0.076t)log_64054(64054)
log_(64054)8200/0.076 = t

as log_x(x^(y)) = y

Answer 9

check your answer by solving for A

Answer 10

just a note ln(x) = log_e(x)

e is just a irrational number it is a pretty neat irrational number discovered by some crazy russian guy

Answer 11

I took 85000 and divided it by 64054 then multiplied it by .076 and got 0.09729 but that cant be right

Answer 12

what part am i doing wrong

Answer 13

Let me do it

Answer 14

82000 = 64054^(.076t)
=
log_(64054)8200=(0.076t)log_64054(64054)
=
log_64054(8200)/0.076 = t

https://www.wolframalpha.com/input/?i=log_64054%288200%29%2F0.076

are you imputing it into your calculator correctly?

Answer 15

log on your calculator is default set to base 10

so you have log_10(x)

to convert to a log of a different base put the number to log(x)/log(base of x)
in your calculator

Answer 16

this is like a different language to me sorry. what is the log for?

Answer 17

logrithm it is a mathematical operation and it is for a ton of different things. You will see it a lot in higher mathematics and in the sciences. It is also how they use to do huge calculations before we were privledged with calculators.

As far as the theory goes I can't really explain it to you.

I will post the rules for you one second

Answer 18

It is mostly used to solve for exponents though

Answer 19

In my math course we have only learned the A=Pe^rt formula and now have to find the missing value for t

Answer 20

well you have to use logrithems to do that, give me a second I'm looking for the laws of logirthems in my pre calc text book I wil ltake ap icture for you and send it to you

Answer 21

ok
Well the basic definition of a logrithm is

log_a(x) = y
is the same as
a^(y) = x

Answer 22

ok thank you for your help, I will give it a try

Answer 23

I will post the protperties for you too if you want them

Answer 24

Ok

Answer 25

Hope this is helpful wanted to test the cameria on my new phone anyways :)

Answer 26

thank you

Answer 27

Just one note I know I already state this but it is a very inportant rule

when taking the ln or log of a variable with an exponent you can always move the exponent down

so for instance log(x^(y)) is the same thing as ylog(x)
ln(x^(y)) is the same thing as yln(x)

this is a very important thing to remember as it is incrediably useful in later algebra

Answer 28

@silkrose39560, would you click on the blue bar "Good Answer" if you're happy with Cuddlepony help :)

Answer 29

t = ln ( 82,000/ 64054)/ .076 = 3.2 yrs ( ~ 4 yrs)