This 4-page document clearly, but concisely, explains everything you need to know about exponentials and logarithms. No prior knowledge of the topic is assumed. I guarantee that after reading these, you will understand the topic much better than you did before. In addition, some example questions h...
Exponentials and Logarithms
1 Logarithms
1.1 Definition
log 𝑘 (𝑎) = 𝑏 𝑎 = 𝑘 𝑏
𝑘 is the base of the logarithm; 𝑏 is the argument; and 𝑎 is the answer (or power).
For example:
log10 (100) = 2 100 = 102
10 is the base; 2 is the argument; 100 is the answer.
1.2 Natural logarithms
Natural logarithms are simply logarithms with base 𝑒. They are most commonly written as ln (𝑥).
ln(𝑥) log 𝑒 (𝑥)
Applying the definition of a logarithm:
log 𝑒 (𝑥) = 𝑘 𝑥 = 𝑒 𝑘
(Note: whenever you see ln (𝑥), the base is 𝑒; when you see just log (𝑥), with no base indicated, the base
is assumed to be 10.)
1.3 The laws of logarithms
General case Natural logs
I’ve included a separate column for natural logs for clarity, but see it is exactly the same, only the base of
the log in the natural case is 𝑒.
(Note: in the general case there is no base; here, I don’t mean specifically base 10, just logs in general; but,
in any other given problem, if there is no base then do assume the base to be 10.)
1
An extra thought: how can log(𝑎𝑛 ) be written?
1.4 A review of exponential laws
𝑧 𝑎 · 𝑧 𝑏 = 𝑧 (𝑎+𝑏)
𝑧𝑎
= 𝑧 (𝑎−𝑏)
𝑧𝑏
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller emmaharris1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £4.89. You're not tied to anything after your purchase.