# Evaluating Basic Logarithms Without a Calculator

Learn to consider fundamental logarithms. Recall that the logarithm of a quantity say a to the bottom of one other quantity say b is a quantity say n which when raised as an influence of b provides a. (i.e. log [base b] (a) = n signifies that b^n = a). Thus, to guage logarithms, we both rewrite the expression as an exponential equation utilizing the definition of logarithm or consider utilizing properties of logarithms.

#evaluatelogarithms #logarithms

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Brian, can you confirm if Kayla still loves Patrick?

I wonder if Kayla still loves Patrick

who's patrick?

i love techers who makes mistakes and then correct them self

because 9:10 of my teachers from primary school to highschool thing they are intelligent and omnipotent.

Prof: Include in your videos the historical methods of calculating logarithms, here is a modern one : Let´s say one wants the log base10 of 2.3, but one has only an 8-digit calculator with the 4 arithmetic operations and the square root, to find Log10(2.3) :

1) Load 2.3 in the calculator 2) square root 10 times the number, < 2.3^(1/1024) >

3) Substract 1 , < 2.3^(1/1024) -1 ) >

4) Multiply by 1024, < 1024 ( 2.3^(1/1024) -1 ) >

5) Multiply by 0.4343, < 0.4343*1024 ( 2.3^(1/1024) -1 ) ,

— That's log(2.3) !! with 4 digits aprox.

— The method comes from the definition of e^x = lim(1+1/x)^x when x goes to infinity,

in this case 1024 replaces infinity, good enough for 4 digit precision. It is not the XVII century ancient method, but gives a flair of it.

Your answer for Log16(4) is incorrect, The answer is just 1/2. The answer cannot be 16^1/2 because 16^1/2=4, and 16^4=/=4

This helped me so much! Thanks!

My math teacher was too confusing.

is someone using a typewriter

is someone using a typewriter

Mr. McLogan's Can you tell me how do I long to dissolve logarithmic equations that need to be like a calculator like log0.3 or log5 but whith not use calculator .

How would we do this without mental calculations?

is the log the number on top

Interesting and compelling way of teaching. Great job

There is a brainless way to find the characteristic of a logarithm. For a logarithm with an argument greater than the base, simply divide the argument by the base until the remainder is less than the base. For example, log 16 base 2 – divide 16 by 2 to get 8, divide 8 by 2 to get 4, divided 4 by 2 to get 2. Four divisions, four powers. For arguments less than the base, consider that 1/log a base b equals log b base a.

I have to ask what's with the banging in the background near the end?.. sounded like a hostage student? 😀

Thanks jason kidd

You are too good at teaching….Thanks , from INDIA

I wish there was more problems! This is really helpful

haha thank you I forgot to finish the problem, I noticed that awhile ago and forgot to make the annotation. THANK YOU I will now have it corrected

number 3 is 1/2 not 16 to he power of 1/2

hahaha that's what math does to use, love hate relationship

Thank you so much! I knew I was forgetting something, it's so obvious now! Thanks again 🙂

Any logarithm with the same base that your are evaluating it for is one. For example log (base 5) of 5 is one because 5 raised to what power equals 5? The answer is one. So knowing that when we rewrite this logarithm by writing the power as a product we can then evaluate log(base18)of 18 to one and then multiply by 11. Therefore the answer is 11. Hope this helps, let me know if you need further help!

How do you solve a logarithm like this, without using a calculator? log(base 18)18^11…. if I use one of the log rules associated with this, I can turn it into this–> 11log(base 18)18… but now what? I'm not sure what to do with the 11, sorry if this makes no sense, I'm running out of options (google and uni has failed me haha)

you are very welcome. happy to help!

That was helpful. Thanks 🙂

hahaha yep!

Kayla <3's Patrick

haha great!

we're reviewing this in my math 122 class at university..he spent 50 minutes lecturing..no one understand..watch this in 3 minutes..easy.

I've been sick for a week and haven't taken notes. This really gave me a boost. Thank you.

your very welcome, let me know how I can help you further

my teacher cannot teach!! this really helped me thank you!

thank you for the input, this video is just a clip from my class. I do plan on making more videos where I explain and go more in depth on the topic. I don't know why I wrote the answer that way. You are correct it is 1/2 I just wrote what it equals for some reason.

Awesome video, but I feel that you should make a more in depth one dealing with variables and stuff that we learn in ALG2Trig.

Also, for log base 16 of 4, shouldn't the answer be 0.5 because you would have to solve for 16^1/2 = log base 16 of four? I think you just wrote an equivalency. Please respond. Thanks.

john jay college that is a unique name. where is that at?

good job!!!!!

we rely need someone like you at John jay college.

thanks

your welcome! really glad I can help you out. Please let me know how else I can help you.

you are making this sound a lot easier than my professor. thanks, it's really helping me a lot 🙂

sweet how did you do?

hat's off to you! great job, like you were a student of my own

your welcome! good luck, let me know how you do!

I SO AGREE

at what time marker?

what IS he trying to say?

No, this helped 100% My teachers made it sound a lot harder than it was and you cleared it up a lot better than they did. please keep it up

you still need help or that helped you? haha not sure what that sound was

so much help, so much help. 2:48 burglars?

0:30 pfft… I don't need to know what a logarithm is, I just need to know how to solve it HA!

0:50 MIND = BLOWN O_x