Răspunsuri

2014-08-09T00:57:01+03:00
A) S= (8 + 8⁴³) *43/2

8¹=(.....8)
8²=(.....4)
8³=(......2)
8⁴=(.....6)
8⁵=(.......8)

se repeta din 4 in 4

43:4=10 rest 3  =>8⁴³=(.....2)

S=[8+(......2)] *43/2=  (......10)*43/2=  (.....5)*43=  (.......5)

b)S=3⁰ +3+3² +....+3⁴²
S=1+3+3²+...+3⁴²

S=(1+3⁴²)*43/2

3¹=(.....3)
3²=(.....9)
3³=(.....7)
3⁴=(.....1)
3⁵=(.....3)

se repeta din 4 in 4

42:4=10 rest 2  =>3⁴²=(.....9)

S=[1+(....9)]*43/2=  (.....10)*43/2=  (.....5)*43=  (.....5)

c)S=8+8¹+8²+....+8⁸⁸

S=(8+8⁸⁸)*89/2

8¹=(.....8)
8²=(.....4)
8³=(.....2)
8⁴=(.....6)
8⁵=(.....8)

se repeta din 4 in 4  88:44=2  =>8⁸⁸=(......8)

S=[8+(.....8)]*89/2=  (.......16)*89/2=  (....8)*89=  (.....2)
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