The Student Room Group

Logarithms

Hh
(edited 2 years ago)
Which bit are you struggling with? Could you post your workings so far?
Reply 2
Original post by Hi.x
1) Express 2 ln x+5 ln y-2 ln xy as a single logarithm

2) express ln((root a^3b^2)/c)


It's not very clear what the actual expression is - is this it?

2ln(x)+5ln(y)2ln(xy)2\ln(x) + 5 \ln(y) - 2\ln(xy)?
1. When adding logarithms you can combine them into one logarithm and make them multiply. When subtracting logarithms you can combine them into one and make them divide. So below I have combined the adding ones to make them multiply and divide everything by subtracting logarithm. Also when you have a number in front of the logarithm you can move it to the front and put it as the power of the logarithm:ln [{x 5}^2] [{y-2}^5] / [xy]^2Sorry it looks complicated
Reply 4
Original post by Hi.x
Is it okay for you to write the workings on paper please and submit them so it’s a little easier to read?

Forum guidelines are that you post your attempts first. There are lots of examples for the basic log rules like
a*log(x) = log(x^a)
log(x) + log(y) = log(xy)
https://www.mathsisfun.com/algebra/exponents-logarithms.html
(edited 2 years ago)

Quick Reply

Latest