Posted by **Sar** on Tuesday, October 4, 2011 at 7:27pm.

I can't get the right answer, where am I going wrong?

7.0x10^9= (6.7x10^9)(2.72^r*3)

1.04 = 2.72^r*3

When I solve for this, I get ln (1.40) = 0.03922 then 0.03922 / 3 = 0.0130

So my r equals 0.0130

BUT the teacher says the answer is

0.05 = r *3

0.02 = r

What did I do wrong? I am so confused!! Help please. Show steps

- math:solving for an exponent. -
**bobpursley**, Tuesday, October 4, 2011 at 8:29pm
is that 2.72^{3r} ?

then 1.0447=2.72^3r

Ln 1.0447=3r *ln 2.72

r= 1/3 (ln1.0447/ln2.72)= 0.0148574093

When you are dealing with logs, you need to keep as many digits as you can. You are correct.

- math:solving for an exponent. -
**Steve**, Tuesday, October 4, 2011 at 8:29pm
1.04 = 2.7^(3r)

ln 1.04 = 3r ln 2.72

but that still does not give .05 = 3r

Typo in problem?

- math:solving for an exponent. -
**Sar**, Tuesday, October 4, 2011 at 8:34pm
No. The math he did was handwritten. I guess he must have made a mistake because this is driving me nuts. Everything listed in my post is CORRECTLY copied from the piece of paper I got it on.

- math:solving for an exponent. -
**Sar**, Tuesday, October 4, 2011 at 8:36pm
Bob, thank you. I thought I was going insane there for a minute. I guess the professor made a mistake. We are all human (but it drives me crazy when I'm trying to study haha)

## Answer This Question

## Related Questions

- math , steve or damon pls - for questions 15 and 16, multiply. write in ...
- Algebra - I'm studying for a test so I want to make sure I'm doing these ...
- 8th Grade math PLEASE CHECK MY ANSWERES - 1.Write the number in standard form: 7...
- chemistry - if the combustion of oil yields 4.0x10^4 kj/kg what mass of oil must...
- chemistry - if the combustion of oil yields 4.0x10^4 kj/kg what mass of oil must...
- math - What is the line of thought or sequence of thought for solving simple ...
- chemistry - 1. (3.0x10^4) divided by (6.2x10^1) = 5x10^2? 2. (4.7x10^-3) divided...
- math - what are the base and exponent in the expression 5.6^4? add (3.4x10^6)+ (...
- MATH/ALGEBRA - I am going over some math homework and need to know if I am ...
- Pre calculus - How do I solve this exponent problem? I understand the exponent ...

More Related Questions