How Do You Solve log_{2}8x^{2} When log_{2}x Equals p?

  • Thread starter thomas49th
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In summary, a log equation is an equation that involves logarithms and is used to solve for unknown exponents or convert between exponential and logarithmic forms. To solve a log equation, isolate the logarithm, apply properties of logarithms, and use basic algebra techniques. Common mistakes include forgetting to apply properties and not checking for extraneous solutions. Tips for solving log equations include rewriting in exponential form and being comfortable with basic algebra and exponent rules.
  • #1
thomas49th
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Homework Statement


Given that [tex]log_{2}x = p[/tex]
a) Find [tex]log_{2}8x^{2}[/tex] in terms of p


The Attempt at a Solution



take the power outside the log

[tex]2log_{2}8x[/tex]

but i can't see what to do next

Any suggestions

Thanks :)
 
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  • #2
I assume you mean:
[tex]{log}_{2}(8x^{2})[/tex]

First things first. How do logs work with products? log(ab) = ?? (In your example, a = 8 and b = x^2.)
 
  • #3
[tex]log_{2}8x^{2}[/tex]

[tex]log_{2}8 + 2log_{2}x[/tex]

[tex]3 + 2p[/tex]

Thanks :)

it was easy!
 
  • #4
Now you've got it! :wink:
 

What is a log equation?

A log equation is an equation that involves logarithms, which are mathematical functions that represent the power to which a base number must be raised to equal a given number. They are used to solve for unknown exponents or to convert between exponential and logarithmic forms of an equation.

How do you solve a log equation?

To solve a log equation, first isolate the logarithm on one side of the equation. Then, use the properties of logarithms, such as the power rule and the product/quotient rule, to simplify the equation and eliminate the logarithm. Finally, solve for the unknown variable using basic algebra techniques.

Can you give an example of solving a log equation?

Sure! Let's say we have the equation log2(x) = 3. To solve for x, we first isolate the logarithm by dividing both sides by log2. This gives us x = 23, which simplifies to x = 8. So the solution to the equation is x = 8.

What are common mistakes when solving log equations?

One common mistake is forgetting to apply the properties of logarithms, which can lead to incorrect simplifications and solutions. Another mistake is forgetting to check for extraneous solutions, which can occur when taking the logarithm of a negative number or when raising a negative number to a fractional power. It's important to always check your solutions in the original equation to ensure they are valid.

Are there any tips for solving log equations?

Yes! It can be helpful to rewrite the logarithm in exponential form, especially when dealing with equations that involve multiple logarithms. Also, remember that the logarithm of 1 is always 0, so if you end up with a logarithm of 1 in your solution, it means there is no real solution to the equation. Additionally, it's important to be comfortable with basic algebra and exponent rules when solving log equations.

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