Q40 of 131 Page 1

Examine, whether the following numbers are rational or irrational:
(i) (√2 + 2)2
(ii) (2-√2)x(2 +√2)
(iii) (√2 +√3)2
(iv)

(i) (2 + 2)2 = (2)2 + 22x2 + (2)2 = 2 + 42 + 4 = 6 + 42 .
     ...  It is an irrational number.

(ii) (2-
2)x(2 + 2) = (2)2 - (2)2 = 4 - 2 = 2 .
      ...  It is a rational number.

(iii) (
2 + 3)2 = (2)2 + 22x3 + (3)2 = 2 + 26 + 3 = 5 + 26
      ...  It is an irrational number.

(iv) = = √2
     ...  It is an irrational number.

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