Question

Se considera numerele:
x= 1 supra 1 - 1 supra 2 + 2 supra 3 - 1 supra 4 + 4 supra 5 - 1 supra 6 + 6 supra 7
y= 1 supra 7 + 1 supra 6 + 1 supra 5 + 1 supra 4 + 1 supra 3 + 1 supra 2 + 1 supra 1 .
Calculati media aritmetica a numerelor x si y. ( Dau cel mai bun raspuns)

Answer 1

x=1/1 -1/2 +2/3 -1/4 +4/5 -1/6 +6/7
y=1/7 +1/6 +1/5 +1/4 +1/3 +1/2 +1/1
Ma=(x+y)/2=(1/1 -1/2 +2/3 -1/4 +4/5 -1/6 +6/7 + 1/7 +1/6 +1/5 +1/4 +1/3 +1/2 +1/1)/2=(2/1 +3/3 +5/5 +7/7)/2=(2+1+1+1)/2=5/2=2,5

Answer 2

Deci, stii ca media aritemtica a celor doua numere este x+y/2
Stiind ca , x+y=1-1/2+2/3-1/4+4/5-1/6+6/7+1/7+1/6+1/5+1/4+1/3+1/2+1=si se va reduce :-1/2 cu +1/2;-1/6 cu 1/6;-1/4 cu 1/4, iar acum mai ramane 
    1+2/3+4/5+6/7+1/7+1/5+1/3+1/2= 1+3/3+5/5+7/7+1+1/2=2+1+1+1/2=5/2.