Aptitude - Square Root and Cube Root - Discussion
Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 6)
6.
If a = 0.1039, then the value of 4a2 - 4a + 1 + 3a is:
Answer: Option
Explanation:
4a2 - 4a + 1 + 3a = (1)2 + (2a)2 - 2 x 1 x 2a + 3a
= (1 - 2a)2 + 3a
= (1 - 2a) + 3a
= (1 + a)
= (1 + 0.1039)
= 1.1039
Discussion:
71 comments Page 5 of 8.
Sayani said:
1 decade ago
I agree with those who has a doubt as why it won't be (2a-1)^2. should we change our ans according to the options available???
BhargaV said:
1 decade ago
4a2 - 4a + 1
(2a)2 - 2(2a)(1) + (1)2
(2a - 1)2
so, 2a - 1 + 3a
Why 1 - 2a is here ???
(2a)2 - 2(2a)(1) + (1)2
(2a - 1)2
so, 2a - 1 + 3a
Why 1 - 2a is here ???
Rakesh. said:
1 decade ago
I do agree with krishan, however 2a-1 is not equal to 1-2a because the value may be the same however, is it postive or negitive value, so can anyone explain on this?
Soumya said:
1 decade ago
Krishna nice explanation.
Pushpa said:
1 decade ago
While I am solving getting (2a-1) or we can write (1-2a) also but why answer differs I mean according to options we should change ?
Mithun said:
1 decade ago
sqrt(4a2-4a+1)=2a-1 or 1-2a?
Tanvi said:
1 decade ago
Yes, Mariapan,
I agree with you.
Why it's not (2a-1)?
I agree with you.
Why it's not (2a-1)?
Mariappan said:
1 decade ago
Square root(a*a)=a
similarly square root{(1-2a)*(1-2a)}=1-2a
but my doubts is that why can't be (2a-1)
Can any one help with this problem ?
similarly square root{(1-2a)*(1-2a)}=1-2a
but my doubts is that why can't be (2a-1)
Can any one help with this problem ?
DhILDAS said:
1 decade ago
FOMULA (a-b) 2 is ok. But how square has gone from (1-2a) 2 and it written as (1-2a) +3a.
Nikhil said:
1 decade ago
The formula => a2 + b2 - 2ab = (a - b)2 can be
a2 + b2 - 2ab = (b - a)2 as well. so we can get it as (2a - 1) +3a . Then the answer will be different.
a2 + b2 - 2ab = (b - a)2 as well. so we can get it as (2a - 1) +3a . Then the answer will be different.
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