(1/2)-2 + (1/3)-2 + (1/4)-2 = ?(a) (61/144) (b) 29 (c) (144/61) (d)

1.	(1/2)-2 + (1/3)-2 + (1/4)-2 = ?(a) (61/144) (b) 29 (c) (144/61) (d) none of these
Answer» (b) 29 We know that, = (1/2)^-2= (2/1)²… [∵ (a/b)^-n = (b/a)ⁿ] = (1/3)^-2 = (3/1)² … [∵ (a/b)^-n = (b/a)ⁿ] = (1/4)^-2 = (4/1)² … [∵ (a/b)^-n = (b/a)ⁿ] Now add, = (2)²+ (3)²+ (4)² = 4 + 9 + 16 = 29

(1/2)-2 + (1/3)-2 + (1/4)-2 = ?(a) (61/144) (b) 29 (c) (144/61) (d) none of these

Answer»

(b) 29

We know that,

= (1/2)^-2= (2/1)²… [∵ (a/b)^-n = (b/a)ⁿ]

= (1/3)^-2 = (3/1)² … [∵ (a/b)^-n = (b/a)ⁿ]

= (1/4)^-2 = (4/1)² … [∵ (a/b)^-n = (b/a)ⁿ]

Now add,

= (2)²+ (3)²+ (4)²

= 4 + 9 + 16

= 29