Question

diketahui barisan aritmatika memiliki u7 = 19 dan u 13 = 37 Dengan demikian nilai U 20 = ?​

Answer 1

Barisan aritmetika

[tex]beda = \frac{37 - 19}{13 - 7} = \frac{18}{6} = 3 \\ \\ Nilai \: u20 \\ u13 + 7b \\ 37 + 7(3) \\ 37 + 21 \\ 58[/tex]

Answer 2

u7=19

u13=37

u20= ?

un=a+(n-1)b

u7=a+6b=19

u13=a+12b=37

a+6b=19

a+12b= 37 _

- 6b= -18

b= -18

-6

= 3

a+6b=19

a+6(3)=19

a+18=19

a=19-18

a=1

u20=a+(n-1)b

=1+(20-1)3

= 1 +19(3)

=1+57

=58