test 12

Question 1

nth term of an arithmetic sequence

Answer 1

an = a1 + (n-1)d

Question 2

constant of an arithmetic

Answer 2

a2-a1=d

Question 3

sum of arithmetic

Answer 3

Sn= n/2 [2(a1) + (n-1)d]

Question 4

nth term of geometric series

Answer 4

an= a1*r^(n-1)

Question 5

constant of geometric series

Answer 5

a2/a1= r

Question 6

sum of geometric series

Answer 6

Sn= [a1-(a1)(r^n)] / (1-r)

Question 7

triangle

Answer 7

1
1x 1y
1x^2 2xy 1y^2
1x^3 3x^2 y 3xy^2 1y^3

Question 8

find the # term of (x+y)^n

Answer 8

[ n! / r!(n-r)! ] x^n-r y^r

r= 1 less than # of term