Algebra Flashcards
What is the quadratic equation formula?
Nth term of an arithmetic series?
Sum of Geometric Series n terms
Sum of first N numbers =
Sum of first N odd numbers =
Sum of first N even numbers =
Arithmetic Mean - Geometric Mean Inequality?
Divisibility Rule by 2
- A number is divisible by 2 if the last digit is 0, 2, 4, 6 or 8.
Divisibility by 3
if sum of digits divisible by 3
Divisibility by 6
if divisible by 3 and by 2
Divisibility by 5
if last digit is 0 or 5
Divisibility by 7
A number is divisible by 7 if forming an alternating sum of blocks of three from right to left gives a multiple of 7
Divisibility by 9
A number is divisible by 9 if the sum of the digits is divisible by 9.
Divisibility by 11
divisible by 11 if the alternating sum of the digits is divisible by 11
Only Even Prime
2
How to find how many factors does a number have?
Increase highest power of each prime factor by 1 and multiply
Finding GCD using Prime Factors
Take lowest power of each prime factor and multiply
How to find Prime Factors?
Make a Factor Tree
How to find how many factors does a number have (using Prime factors) ?
Find the Prime Factors
Then - Add 1 to each exponent in the prime factorization and multiply
LCM x GCD of two numbers =
Product of the numbers x.y
x . y = LCM(x,y) multiplied by GCD(x,y)
