Revision as of 19:01, 6 January 2020

Memorize

These are things you need to memorize.

Order of operations: first parenthesis, then exponents, then multiplication/division/modulus, then addition and subtraction. And left to right.
Powers/exponents
- 2¹⁰ = 1024, roughly 1 thousand
- 2^a+b = 2^a * 2^b
- y^a+b = y^a * y^b
- 2^-a = 1 / (2^a)
- 2²⁰ = 1024 × 1024, roughly 1 million
- 2³⁰ = 1024 × 1024 × 1024, roughly 1 billion
Logarithms
- log_bx = y, means b^y = x, for any b > 1
- log_bx = log_cx / log_cb, for any b > 1, c > 1
- log₂10 is about 3.32
- log_b(xy) = y log_b x, for any b > 1

@@ Line 10: / Line 10: @@
 ** 2<sup>30</sup> = 1024 × 1024 × 1024, roughly 1 billion
 * ''Logarithms''
-** log<sub>b</sub>x = y, means by = x, for any b > 1
+** log<sub>b</sub>x = y, means b<sup>y</sup> = x, for any b > 1
 ** log<sub>b</sub>x = log<sub>c</sub>x / log<sub>c</sub>b, for any b > 1, c > 1
 ** log<sub>2</sub>10 is about 3.32
 ** log<sub>b</sub>(xy) = y log<sub>b</sub> x, for any b > 1