Question

Daca a=2/3×5 +3/5×8 +4/8×12 sa se arate ca aparține (1/10;1/2) VA ROG MULT URGENT!!!

Answer 1

Explicație pas cu pas:

a=2/3*5+3/5*8+4/8*12=>

a=(5-3)/3*5+(8-5)/5*8+(12-8)/8*12=>

a=5/3*5-3/3*5+8/5*8-5/5*8+12/8*12-

-8/8*12 =>

a=1/3-1/5+1/5-1/8+1/8-1/12 =>

a=1/3-1/12 => a=4/12-1/12=>a=3/12 =>

a=1/4

a€(1/10,1/2)<=>

1/10<a<1/2 <=>

1/10<1/4<1/2

Cum 1/10<1/4 (4<10) si 1/4<1/2(2<4) =>

1/10<1/4<1/2 (Adevarat) => a€(1/10,1/2)