Question

Se considera numarul a=1 supra radical din 2 + 2 supra radical din 8+ 3 supra radical din 18 + 4 supra radical din 32. Aratati ca a= 2 radical din 2.
Urgent!!!!!!!

Answer 1

1/√2 + 2/√8 + 3/√18 + 4/√32=
Rationalizam numitorii 
1/√2=√2/2
2/√8=2/2√2=1/√2=√2/2
3/√18=3/3√2=1/√2=√2/2
4/√32=4/4√2=1/√2=√2/2

√2/2+√2/2+√2/2+√2/2=4√2/2=2√2 ceea ce era de demonstrat

Answer 2

a=1/√2+2/√8+3/√18+4/√32= 1/√2+ 2/2√2+ 3/3√2+ 4/4√2= 1/√2+1/√2+ 1/√2+ +1/√2= 1/√2*4=4√2

       /*√2
a=4/√2 =4√2/2=2√2