Mastering Logarithms: Simplifying Complex Expressions with Multiple Logs

In summary, the conversation discusses the possibility of putting the expression 3log2(x)-4log(y)+log2(5) into a single logarithm. The conversation also mentions attempting various methods to find a solution. An attempt at a solution using logarithmic formulas is provided, but it is noted that there are three logarithms present, indicating that the solution is not yet in a single logarithm form.
  • #1
rashida564
220
6

Homework Statement


can we put
3log2(x)-4log(y)+log2(5)
in one logarithm
it try in all the ways but i can't find the solution .

Homework Equations


loga(b)=logx(b)/logx(a)
log(b*a)=log(b)+log(a)

The Attempt at a Solution


log2(5x^3)-log(y^4)
log2(5x^3)-log2(y^4)/log2(10)
 
Physics news on Phys.org
  • #2
rashida564 said:

Homework Statement


can we put
3log2(x)-4log(y)+log2(5)
in one logarithm
it try in all the ways but i can't find the solution .

Homework Equations


loga(b)=logx(b)/logx(a)
log(b*a)=log(b)+log(a)

The Attempt at a Solution


log2(5x^3)-log(y^4)
log2(5x^3)-log2(y^4)/log2(10)
There are also formulas for ##\log_2 a - \log_2 b## and ##\log_2 a^c## which you need here.
 
  • #3
i don't know that i should do
 
  • #4
Well you have
rashida564 said:
log2(5x^3)-log(y^4)
log2(5x^3)-log2(y^4)/log2(10)
which I read as ##\log_2 5x^3 - \log_{10} y^4 = \log_2 5x^3 - \frac{1}{\log_2 10}\log_2 y^4##.
Now you can use ##c \cdot \log_2 a = \log_2 a^c## and ##\log_2 a - \log_2 b = \log_2 \frac{a}{b}## to write all in a single ##\log_2## expression. (Of course with a constant ##c=\log_2 10##.)
 
  • #5
log2(5x^3/((log2y^4)^(1/log2(10))))
then who i can write it as a single log i see three logs
 
  • #6
rashida564 said:
log2(5x^3/((log2y^4)^(1/log2(10))))
then who i can write it as a single log i see three logs
You cannot get rid of the constant ##\log_2 10## if you are dealing with two different basis. Are you sure they are meant to be different?
And you have one ##\log_2## too many in the application of the formulas.
 
  • #7
sory for that
 
  • #8
sorry*
 

1. What are logarithms and why are they important in scientific calculations?

Logarithms are mathematical functions that are used to simplify complex exponential expressions. They are important in scientific calculations because they allow us to condense large numbers into more manageable values and make complex calculations easier to solve.

2. How do I combine and simplify multiple logarithms in an expression?

To combine and simplify multiple logarithms, you can use the properties of logarithms such as the product, quotient, and power rules. These rules allow you to rewrite the expression in a simpler form by combining the logarithms with the same base and applying basic algebraic manipulations.

3. Can I use a calculator to solve logarithmic equations?

Yes, most scientific calculators have a logarithm function that allows you to solve logarithmic equations. However, it is important to know the properties of logarithms and how to simplify expressions by hand before using a calculator.

4. How can I check if my answer to a logarithmic problem is correct?

You can check your answer by plugging it back into the original equation and simplifying both sides to see if they are equal. You can also use a calculator to verify your answer.

5. Are there any common mistakes to avoid when working with logarithms?

One common mistake is forgetting to apply the logarithm rules when simplifying expressions. Another mistake is forgetting to check for extraneous solutions, which can occur when taking the logarithm of both sides of an equation.

Similar threads

  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
  • Precalculus Mathematics Homework Help
Replies
10
Views
605
  • Precalculus Mathematics Homework Help
Replies
12
Views
2K
  • Precalculus Mathematics Homework Help
Replies
10
Views
2K
  • Precalculus Mathematics Homework Help
Replies
9
Views
2K
  • Precalculus Mathematics Homework Help
Replies
16
Views
5K
  • Precalculus Mathematics Homework Help
Replies
11
Views
5K
  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
  • Precalculus Mathematics Homework Help
Replies
6
Views
2K
Back
Top