Question

What is the feeling being conveyed upon hearing the song Burung kakatua??

Answer 1

Answer:

2 is the common difference of an AP

Given:

a (first term of the arithmetic progression) = 5

S_{4}=\frac{1}{2}\left(S_{8}-S_{4}\right)S

4

= 21(S 8−S4)

To find:

d (Common Difference) = ?

Solution:

The general sequence of an AP is a ,a + d ,a + 2d ,a + 3d,…

Substituting a=5 then

5, 5 + d,5 + 2d,5 + 3d,5 + 4d,5 + 5d,5 + 6d,5 + 7d,,..

Let the first 4 terms be 5,5 + d,5 + 2d,5 + 3d

And let the next 4 terms be = 5 + 4d,5 + 5d,5 + 6d,5 + 7d

And \bold{S_{4}=\frac{1}{2}\left(S_{8}-S_{4}\right)----(1)}S

4

=21(S8−S4 )−−−−(1)

By substituting these values in (1)

$$\begin{lgathered}\begin{array}{l}{5+5+d+5+2 d+5+3 d} \\ {\qquad \qquad=\frac{1}{2}(5+4 d+5+5 d+5+6 d+5+7 d)}\end{array}\end{lgathered}$$

20+6d=10+11d

10=5d

d=2