The Student Room Group

Logarithms

Prove that (1/logx(xy^2))+(1/logy(xy^2))+(1/log2(xy^z))=1
Reply 1
Original post by cathedra x
Prove that (1/logx(xy^2))+(1/logy(xy^2))+(1/log2(xy^z))=1

Have you typed that correctly, should there be a z, can you use more brackets with the logs as well it isn't as clear as it could be.
Reply 2
Sorry I couldn't type it clearly enough. I'm struggling to type it as it should be. It's supposed to be the expression 1 "divided by log of (xy^2)-not (xy)^2- to the base x" plus the expression "1 divided by log of (xy^2)" plus the expression "1 divided by log of (xy^z) to the base 2". Prove that this is equal to 1. And yes, there is a z. By the way, thanks for your reply and for your patience.
Reply 3
Original post by cathedra x
Sorry I couldn't type it clearly enough. I'm struggling to type it as it should be. It's supposed to be the expression 1 "divided by log of (xy^2)-not (xy)^2- to the base x" plus the expression "1 divided by log of (xy^2)" plus the expression "1 divided by log of (xy^z) to the base 2". Prove that this is equal to 1. And yes, there is a z. By the way, thanks for your reply and for your patience.


So is this what you mean?
1logx(xy2)+1logy(xy2)+1log2(xyz)=1 \displaystyle \frac{1}{\log_x (xy^2)} +\frac{1}{\log_y (xy^2)}+\frac{1}{\log_2 (xy^z)}=1 ?
(edited 7 years ago)
Original post by cathedra x
Sorry I couldn't type it clearly enough. I'm struggling to type it as it should be. It's supposed to be the expression 1 "divided by log of (xy^2)-not (xy)^2- to the base x" plus the expression "1 divided by log of (xy^2)" plus the expression "1 divided by log of (xy^z) to the base 2". Prove that this is equal to 1. And yes, there is a z. By the way, thanks for your reply and for your patience.


Any chance of a picture? Might make it a bit clearer, I'm still struggling to understand the question
Reply 5
Yes, thank you. That's the equation
Reply 6
Original post by an_atheist
Any chance of a picture? Might make it a bit clearer, I'm still struggling to understand the question


Sorry, the question doesn't come with a picture or diagram.
Original post by B_9710
So is this what you mean?
1logx(xy2)+1logy(xy2)+1log2(xyz)=1 \displaystyle \frac{1}{\log_x (xy^2)} +\frac{1}{\log_y (xy^2)}+\frac{1}{\log_2 (xy^z)}=1 ?


Pretty sure this isn't an identity; either there's a mistake or details about the values of x,y,zx,y,z are missing.
Reply 8
Original post by IrrationalRoot
Pretty sure this isn't an identity; either there's a mistake or details about the values of x,y,zx,y,z are missing.


Same thoughts here.
Reply 9
OK, thanks. I'll check the question again and get back to all of you.
i think that the third base should be z not 2
Original post by the bear
i think that the third base should be z not 2


The problem works if you replace the 2 with a y and the z with a 2.

Quick Reply

Latest