Write an explicit formula for each sequence Arithmetic sequences : an=a1+d(n-1)
1) 2, 4, 6, 8
2) 15 , 12, 9 , 6
Geometric sequences : gn=g1 *r (n-1 )
3) 5, 10 , 20, 40
4) 1, -2 , 4 , -8

AnsRecursive Formula: an= an-1 + d

Used to find the next term in a sequence using a common difference.

Example: 2, 4, 6, 8, 10

nth term:  1, 2, 3, 4, 5,

a1 = 2        Common Difference is 2

a2 = a2-1 + 2

a2 = a1 +2

a2 = 2 + 2

a2 = 4

Explicit formula: an = an= a1 + d (n-1)

Used to find any term in the sequence depending on the term #.

6, 12, 18, 24, 30, 36, 42, 48, 54...

1,  2,   3,  4,   5,    6,   7,  8,   9,  

Find the term in the sequence if the term number is 28.

a28 = 6 + 6 (28-1)

a28 = 168

the probability is 0

(sin 42)/31. = sinx)/37

sinx = 37 (sin42)/31

= 37× 0.66/31 = 0.787

x= 51.9

other angle opposite to y = 180-51.9-42

= 180- 93.9 =86.1

so

sin42)/31 = sin 86.1)/y

0.021 = 0.997 /y

y= 0.997/0.021 =47.47