Algebra Flashcards
1
Q
Sum of roots in quadratic equation
A
-B/A
2
Q
Product of roots in quadratic equation
A
C/A
3
Q
r^th term in binomial expansion (a+b)^n
A
C(n,r-1)(a^(n-r+1))(b^(r-1))
4
Q
Sum of n numbers in arithmetic progression
A
sn = (n/2)*(a1+an)
5
Q
n^th number in arithmetic progression
A
an = a1+(n-1)*d
6
Q
n^th number in geometric progression
A
an = a1*r^(n-1)
7
Q
Sum of n numbers in geometric progression
A
sn = a1*((1-r^n)/(1-r)) where r is not equal to 1
8
Q
Sum of coefficients of the expansion of (x+y)^2
A
Sum = (coeff. of x + coeff. of y)^n
9
Q
Sum of exponents of the expansion of (x+ y)^2
A
Sum = n(n+1)
