Is (a + b)^2 a^2 + b^2 ? (1) a = 0 (2) b

Question

Is (a + b)^2 > a^2 + b^2 ?

(1) a = 0
(2) b < 0

LaveenaPanchal · Answer

(a+b)^2 > a^2+b^2
a^2+2ab+b^2>a^2+b^2
is 2ab>0?

Statement 1. a=0, then 2ab = 0. Answer is No. Sufficient.
Statement 2. b<0. No information about a. Not Sufficient.

so the answer is A.

chetan2u · Answer

Let us simplify the question. (a + b)^2 > a^2 + b^2 a^2+2ab+b^2 > a^2 + b^2.........2ab>0 (1) a=0 Is 2*0*b>0? Or Is 0>0?......NO Sufficient (2) b<0 Is 2ab>0? If a>0, then no. For example, a=2 and b=-2, then 2ab = 2*2*-2=-4<0. If a<0, then yes. For example, a=-2 and b=-2, then 2ab = 2*-2*-2=8>0. Insufficient A

harshtandel838 · Answer

Solving the inequality,
(a + b)^2 > a^2 + b^2
We get,  Is 2ab > 0 or not?

1)  a = 0, so inequality will be 
  Is 0 > 0 ?   NO 
  SUFFICIENT

2)  b < 0, we don’t know whether a is positive or negative.
  INSUFFICIENT

SO, answer is A

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Enchanting · Answer

• (a+b)^2 = a^2+b^2+2ab o If 2ab>0 , then (a+b)^2 > a^2+b^2 o If 2ab < 0 , then (a+b)^2 < a^2+b^2 o If 2ab = 0, then (a+b)^2 = a^2+b^2 Statement 1. • a = 0 o 2ab=0 o (a+b)^2 = a^2+b^2 Statement 1 is sufficient to answer. Statement 2. • b < 0 o If a = 0, then 2ab =0 . o If a < 0, then 2ab > 0 . o If a>0 , then 2ab < 0 . Statement 2 is not sufficient to answer the question. Answer:- Option A

Is (a + b)^2 > a^2 + b^2 ? (1) a = 0 (2) b < 0

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