1.
證明根號1加根號2不等於根號3
提供另解,
1^2+[sqr(2)]^2=[sqr(3)]^2
thus, 1,sqr(2),sqr(3) can be lengths of the three side of a right angle triangle.
(By converse of Pyth Thm)
thus, by triangle inequality, a+b>c,
we have 1+sqr(2)>sqr(3),
hence 1+sqr(2)is not equal to sqr(3)