áãÏÇ áÇ ÊÓÇÚÏæäí..............

[NADIR22]

ãä ÝÖáßãÇÍÊÇÌ Íá åÏå ÇáÊãÇÑíä Ýí ãÇÏÉ ÇáÑíÇÖíÇÊ
72Õ172
88Õ173
27Õ168

[ÅÓÜÑÂÁ ßÜæËÜÜÑ]

Ýí ÇíÉ ãÇÏÉ

[ÅÓÜÑÂÁ ßÜæËÜÜÑ]

ÇÐÇ ßÇäÊ ãÇÏÉ ÇáÑíÇÖíÇÊ ÝÇáÍáæá ßÇáÊÇáí
72
1-ÍÓÇÈ ÇáÍÏæÏ:
äÖÚ n=0
U2=2U1-U0=8-1=7
äÖÚn=1
U3=2U2-U1=14-4=10
äÖÚn=2
U4=2U3-U2=20-7=13
äÖÚn=3
U5=2U4-U3=26-10=16

2-ÅËÈÇÊ Ãä ÇáãÊÊÇáíÉ Un ÍÓÇÈíÉ æ ÊÍÏíÏ ÇÓÇÓåÇ q :
Un+2=2Un+1-Un
æ ãäå Un+2=Un+1+Un+1+Un
Un+2-Un+1=Un+1-Un
ÅÐä Un ãÊÊÇáíÉ ÍÓÇÈíÉ
ÍÓÇÈ ÇáÃÓÇÓ q
q=U5-U4=16-3
æ ãäå q=3

3-
Un=Ua+(n-a)q
Un=U5+(n-5)3
Un=16+3n-15
Un=3n+1

4-ÅíÌÇÏ ÑÊÈÉ ÇáÍÏ ÇáÐí ÞíãÊå 361 :
Un=3n+1
361=3n+1
3n=360
n=120
5-ÍÓÇÈ ÇáãÌãæÚ : S=U0+U1+U2+....+U2n+1
S=2n/2*(1+U2n+1)l
S=n(1+1+(2n-1)3)l
S=n(2+6n-3)l
S=n(6n-1)l