Question

Вычислите x +y дробь 2 √xy если:
a) x = 2√7 - 5, y = 5 + 2√7
б) x = 1 дробь √2 + 1, y = 1 дробь √2 - 1

Answer 1

а) ((2*(7^1/2)-5)+(5+2*(7^1/2))/2*(2*(7^1/2)-5)*(2*(7^1/2)+5))^1/2=
4*(7^1/2)/2*(4*7-25)^1/2=
2*(7^1/2)/(28-25)^1/2= 2*(7/3)^1/2;
б) (((2^1/2-1)+(2^1/2+1))/(2^1/2+1)(2^1/2-1)):
2*(1/(2^1/2+1)(2^1/2-1))^1/2=
(2*2^1/2/(2-1))/2*(1/(2-1))^1/2=
2*2^1/2/2=2^1/2.