Math Is Fun Forum

nando88

Member

Registered: 2013-07-07

Posts: 6

Apply logarithms to both sides of an equation

I have an equation that looks something like this= a^2+b=c and I want to apply logarithms to both sides of the equation, can someone please tell me how would the equation look like after applying the logarithm to both sides?
Thanks in advance!

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Apply logarithms to both sides of an equation

Hi;

This is your equation?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

nando88

Member

Registered: 2013-07-07

Posts: 6

Re: Apply logarithms to both sides of an equation

yes

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Apply logarithms to both sides of an equation

When you take the log of both sides you get:

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,643

Re: Apply logarithms to both sides of an equation

hi

I'm trying to anticipate your next step; maybe like this would be useful:

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

nando88

Member

Registered: 2013-07-07

Posts: 6

Re: Apply logarithms to both sides of an equation

and if I had something like log(3^3+3^4)=log(3^7), how could I simplify log(3^3+3^4). How could you solve this, because I tried adding what's inside the parenthesis and then applying logarithm and it didn't work. How can I solve this equation?

Last edited by nando88 (2013-07-08 00:15:15)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Apply logarithms to both sides of an equation

3^3 + 3^4 does not equal 3^7

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

nando88

Member

Registered: 2013-07-07

Posts: 6

Re: Apply logarithms to both sides of an equation

How could I apply a logarithm to 3^3+3^4?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Apply logarithms to both sides of an equation

You could apply it to

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

EbenezerSon

Member

Registered: 2013-07-04

Posts: 554

Re: Apply logarithms to both sides of an equation

and if I had something like log(3^3+3^4)=log(3^7), how could I simplify log(3^3+3^4). How could you solve this, because I tried adding what's inside the parenthesis and then applying logarithm and it didn't work. How can I solve this equation?

Check very well from the source I suppose there should be some kind of: log2=3.142 or Log3=616 or something,  so that you can substitute into the equation, because to me this log could be solved to some extent but good final solution is not possible. If something of that kind is not provided.

Last edited by EbenezerSon (2013-07-08 02:56:15)

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I know only one thing - that is that I know nothing

nando88

Member

Registered: 2013-07-07

Posts: 6

Re: Apply logarithms to both sides of an equation

whe will a log of a number return a whole number?

EbenezerSon

Member

Registered: 2013-07-04

Posts: 554

Re: Apply logarithms to both sides of an equation

whe will a log of a number return a whole number?

Sometimes the when a log question is given, one could arrive on  figures which you must substitute them into it.  Actually the question setter,  will set it in such way that you will arrive on those whole numbers.  An finally you will substitute.

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I know only one thing - that is that I know nothing

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Apply logarithms to both sides of an equation

whe will a log of a number return a whole number?

Hi nando

Welcome to the forum!

Well, it depends on the base of the logarithm. If you have the logarithm base 10, then the logarithm of the integer powers of ten will be integers.

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“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

EbenezerSon

Member

Registered: 2013-07-04

Posts: 554

Re: Apply logarithms to both sides of an equation

See the following:
Solve the following logarithm:

Log6 + Log10.  Given that, Log2=3.14 Log3=616

= Log(2*3)+Log10 = Log2+log3 +log10= (3.14+616+1) = 620.14.

Note that, Log10=1

This is what I mean.

I hope you cotton.

Last edited by EbenezerSon (2013-07-08 03:25:52)

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I know only one thing - that is that I know nothing

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Apply logarithms to both sides of an equation

Given that, Log2=3.14 Log3=616

These values are not correct.

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“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

EbenezerSon

Member

Registered: 2013-07-04

Posts: 554

Re: Apply logarithms to both sides of an equation

Yes I did it as an example, It not the real values.

Thanks.

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I know only one thing - that is that I know nothing

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Apply logarithms to both sides of an equation

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.