# math - natural logs

posted by .

Find the EXACT solution to
e^(1-x) = 4^x

You must use logs, not just a calculator.

• math - natural logs -

take ln of both sides

ln( e^(1-x) = ln (4^x)
(1-x)lne = x(ln4)
1-x = xln4
xln4 + x = 1
x(ln4 + 1) = 1
x = 1/(ln4 + 1)
= appr. .419

check
LS = e^.581 = 1.7877
RS = 4^.416 = 1.7877 (not bad)

## Similar Questions

1. ### solving for x math

2e^(4x^2)=3 how do i solve for x. do i use the ln methode because i don't know how to do that. by calculator, i got x=.168 but i don't know how to show my work. please help me solve for x. Take natural logs of both sides. ln 2 + 4 …
2. ### chemistry

help required in calculating the pH value of a .84 mols per litre solution of sulfuric acid. I understand that pH = -log 10 (2x 0.84), I am not very experienced with logs and need assistance as to which keys to press on the scientific …
3. ### Precalculus

.5=e^(-20t) I am assuming this involves logs but we did't really learn logs. Anyone care to walk me through with a calculator. Have the Ti-83
4. ### Math

Logs are stacked up in apile as shown in the figure. The top row has 15 logs and the bottom row has 21 logs. How many logs are in the stack?
5. ### trigonometry

(3^m)(5^(m+1))=12^(2m-1) not sure how to solve this but I think you use natural logs?
6. ### math logs

solve 3^(2x+1) = 9^(2x-1) using base 3 logs
7. ### algebra

200 logs are stacked so that 20 logs at bottom row 19 in the next ,18 in the next and so on.In how many rows can 200 logs be arranged and how many are there on the top row ?
8. ### Physics

Raft made of 2.2m long pine logs.Average diameter of logs 26cm.How many logs are needed to strap together to build raft to hold max 4 people?
9. ### Physics

Raft made of 2.2m long pine logs.Average diameter of logs 26cm.How many logs are needed to strap together to build raft to hold max 4 ?
10. ### Physics

PART 1 Raft made of 2.2m long pine logs with Average diameter of logs 26cm.How many logs are needed to strap together to build raft to hold max 4 people?

More Similar Questions