Rewriting Expression w/Log Laws: x^10*sqrt((y^19)/(z^7))

And you could also write it as ln(sqrt(xy))= ln((x1/2)(y1/2))= ln(x1/2)+ ln(y1/2)= (1/2)ln(x)+ (1/2)ln(y) In summary, the expression ln (x^10*sqrt((y^19)/(z^7))) can be rewritten using the laws of logarithms as 10 ln(x) + (19/2) ln(y) - (7/2) ln(z). The square root can be treated as a 1/2 power, and using the law ln(ab) = ln(a) + ln(b), we can simplify the expression further.
  • #1
3.141592654
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Homework Statement



Use the Laws of logarithms to rewrite the expression in a form with no logarithm of a product, quotient or power.
ln (x^10*sqrt((y^19)/(z^7))) = a ln(x)+b ln(y)+c ln(z)


Homework Equations



ln (x^a)=a ln(x)

The Attempt at a Solution



I know that it will start =10 ln(x), but I don't know what the square root implies. To specify, if I had the equation ln(sqrt(xy)), I thought the answer would be ln(x)+2 ln(y), but this isn't the case. Can anyone explain what happens to the square root when rewriting this expression? Thanks for your help!
 
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  • #2
Taking the square root of a quantity is the same as raising that quantity to the 1/2th power. In other words, the square root is interchangeably just an exponent of 1/2.

- Warren
 
  • #3
3.141592654 said:

Homework Statement



Use the Laws of logarithms to rewrite the expression in a form with no logarithm of a product, quotient or power.
ln (x^10*sqrt((y^19)/(z^7))) = a ln(x)+b ln(y)+c ln(z)


Homework Equations



ln (x^a)=a ln(x)
Another very relevant equation for this problem is ln(ab)= ln(a)+ ln(b).

The Attempt at a Solution



I know that it will start =10 ln(x), but I don't know what the square root implies. To specify, if I had the equation ln(sqrt(xy)), I thought the answer would be ln(x)+2 ln(y), but this isn't the case. Can anyone explain what happens to the square root when rewriting this expression? Thanks for your help!
As chroot told you sqrt is "1/2" power. Notice that even if you had 2nd power, you would NOT have ln((xy)2)= ln(x)+ 2 ln(y). ln((xy)[2= 2ln(xy)= 2[ln(x)+ ln(y)]= 2ln(x)+ 2ln(y).

Now, ln(sqrt(xy))= ln((xy)1/2)= what?
 
  • #4
thanks for your help, both of you, I was able to figure out the problem with this!
Halls of Ivy,
ln(sqrt(xy))= ln((xy)1/2)= 1/2ln(xy)= 1/2ln(x)+ 1/2ln(y)
 
  • #5
Exactly!
 

1. How do I rewrite this expression using log laws?

To rewrite this expression using log laws, we first need to understand the basic properties of logarithms. The logarithm of a number represents the power to which a base number must be raised to equal that number. In this expression, we have a product and a quotient, which can be simplified using the properties of logarithms. We can use the power rule and the quotient rule to rewrite the expression as logx(x10) + 1/2logx(y19) - 1/2logx(z7).

2. What is the base number for the logarithm in this expression?

The base number for a logarithm is the number that is raised to a certain power. In this expression, the base is represented by the "x" in logx. This means that the logarithm is the power to which the base number "x" needs to be raised to equal the value inside the parentheses.

3. How do I simplify the expression using the properties of logarithms?

To simplify the expression, we can use the power rule, which states that logb(xm) = mlogb(x), and the quotient rule, which states that logb(x/y) = logb(x) - logb(y). Using these rules, we can rewrite the expression as logx(x10) + 1/2logx(y19) - 1/2logx(z7), which can be further simplified to 10 + 19/2logx(y) - 7/2logx(z).

4. Can I use any base number for the logarithm in this expression?

Yes, you can use any base number for the logarithm in this expression. However, it is important to note that using different base numbers will result in different values for the logarithm. The most commonly used base numbers are 10 and e (the natural logarithm), but any positive number can be used as the base for a logarithm.

5. How does rewriting this expression using log laws make it simpler?

Using log laws to rewrite this expression can make it simpler because it breaks down the expression into smaller, more manageable parts. This allows us to simplify each part individually, making the overall expression easier to understand and work with. In addition, using log laws can help us see patterns and relationships between different parts of the expression, which can be useful in solving equations or performing other mathematical operations.

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