TheCATExam
Sign in

CAT 2005 — QA Question 26

Square root of SurdsEasy

Let x = 4+4-4+4-....to infinity. Then x equals

Answer & solution

Correct answer: 13 + 1 2

  • A

    3

  • B

    (13-12)

  • (13+12)

  • D

    13

Solution

x = 4+4-4+4-....to infinity

∴ x2 - 4 = 4-4+4-.... to infinity

∴ (x2 - 4)2 - 4 = - 4+4-...to infinity

∴ (x2 - 4)2 - 4 = - x

Now, substituting options, we find that only option (c) satisfies the above equation.

Hence, option (c).

Related Square root of Surds questions

See all Surds & Indices questions →
CAT 2005 QA Q26: Let x = 4 + 4 - 4 + 4 - . . . . t o i n f i n i t y . Then x equals — Solution | TheCATExam