Răspuns :
Răspuns:
Explicație pas cu pas:
a)
1 + 2 + 3 + ... + 99
progresie aritmetica cu 99 termeni, a1 = 1; a99 = 99; r = 1
S99 = 99(1 + 99)/2 = 4950
1,4^4950
_______________
b)
2 + 4 + 6 + .... + 100
progresie aritmetica
a1 = 2
an = 100
r = 2
an = a1 + (n - 1)r
100 = 2 + 2(n - 1) = 2 + 2n - 2
2n = 100
n = 50 (termeni in suma)
S50 = 50(2 + 100)/2 = 2550
2,5^2550
_______________
c)
1 + 3 + 5 + ... + 101
progresie aritmetica cu a1 = 1; an = 101; r = 2
101 = 1 + 2(n - 1) = 1 + 2n - 2 = 2n - 1
2n = 102
n = 51
S51 = 51(1 + 101)/2 = 2601
2,5^2601
_____________
d)
2*3*5*7 + 1000 = 210 + 1000 = 1210
1,7^1210
Explicație pas cu pas :
a )
[tex]1.4 \cdot {1.4}^{2} \cdot {1.4}^{3} \cdot ... \cdot {1.4}^{99} = \\ \\ \\ {1.4}^{1 + 2 + 3 + ... + 99} = \\ \\ \\ {1.4}^{99 \cdot 100 \div 2} = \\ \\ \\ {1.4}^{99 \cdot 50} = \\ \\ \\ {1.4}^{4950} [/tex]
b )
[tex] {2.5}^{2} \cdot {2.5}^{4} \cdot {2.5}^{6} \cdot ... \cdot {2.5}^{100} = \\ \\ \\ {2.5}^{2 + 4 + 6 + ... + 100 } = \\ \\ \\ {2.5}^{2 \cdot (1 + 2 + 3 + ... + 50)} = \\ \\ \\ {2.5}^{2 \cdot (50 \cdot 51 \div 2)} = \\ \\ \\ {2.5}^{50 \cdot 51} = \\ \\ \\ {2.5}^{2550} [/tex]
c )
[tex]2.25 \cdot {2.25}^{3} \cdot {2.25}^{5} \cdot ... \cdot {2.25}^{101} = \\ \\ \\ {2.25}^{1 + 3 + 5 + ... + 101} = \\ \\ \\ {2.25}^{(1 + 2 + 3 + ... + 102) - (2 + 4 + 6 + ... + 102)} = \\ \\ \\ {2.25}^{(102 \cdot 103 \div 2) - 2 \cdot (1 + 2 + 3 + ... + 51)} = \\ \\ \\ {2.25}^{(51 \cdot 103) - 2 \cdot (51 \cdot 52 \div 2)} = \\ \\ \\ {2.25}^{(51 \cdot 103) - (51 \cdot 52)} = \\ \\ \\ {2.25}^{51 \cdot (103 - 52)} = \\ \\ \\ {2.25}^{51 \cdot 51} = \\ \\ \\ {2.25}^{2601} [/tex]
d )
[tex] { {( { ({(1.7}^{2}) }^{3} )}^{5}) }^{7} \cdot {1.7}^{1000} = \\ \\ \\ {1.7}^{2 \cdot 3 \cdot 5 \cdot 7} \cdot {1.7}^{1000} = \\ \\ \\ {1.7}^{210} \cdot {1.7}^{1000} = \\ \\ \\ {1.7}^{210 + 1000} = \\ \\ \\ {1.7}^{1210} [/tex]