Page 259 - aljaber

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( ). ()
1 S6 = 1 2 26 − 1 = 2 × 63 = 7
18 × 2−1 18
18

.a1, a1r, a1r 2, … :( )

. 0, d, 2d, …

a1 + 0 = 1 ⇒ a1 = 1 cn = an + bn

( ) a1r + d = 1 ⇒ r + d = 1
( ) a1r2 + 2d = 2 ⇒ r2 + 2d = 2

( ) −2 ( )

.r(r − 2) = 0 .r 2 − 2r = 0

.d = −1 .(r ≠ 0 ) r = 2

{an }

( )a1 r10 − 1 = 210 − 1 = 1023
r −1 2 −1

{bn }

10  0 + 9 ×(−1) = −45
2

{cn }

.1023 + (−45) = 978

.d = 1 a1 = k2 + 1 :( ) ()