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 7 of 8.
Arpit said:
1 decade ago
4 = 2^2 and also 4=(-2)^2.
So sqrt 4 = 2, -2.
So sqrt 4a^2 -4a +1 = +(2a-1),-(2a-1).
So we have choose any one of these such it satisfies the options available.
+(2a-1) + 3a = 5a-1 = -1.5195 such option is not available.
-(2a-1) + 3a = a+1 = 1.1039 this one is option C.
So sqrt 4 = 2, -2.
So sqrt 4a^2 -4a +1 = +(2a-1),-(2a-1).
So we have choose any one of these such it satisfies the options available.
+(2a-1) + 3a = 5a-1 = -1.5195 such option is not available.
-(2a-1) + 3a = a+1 = 1.1039 this one is option C.
Abhirup said:
1 decade ago
Sq root of 4 is (+ or -) 2.
Because when we do (+ or - 2)^2 in both cases its +4.
Similarly +(1 - 2a)^2 is true and as well as -(1 - 2a)^2 i.e. (2a-1)^2 is also true.
How ever the answer in two cases are different.
So there must be an other answer except option C.
Because when we do (+ or - 2)^2 in both cases its +4.
Similarly +(1 - 2a)^2 is true and as well as -(1 - 2a)^2 i.e. (2a-1)^2 is also true.
How ever the answer in two cases are different.
So there must be an other answer except option C.
Krishna said:
1 decade ago
In a-b formula a<b is the condition so 1-2a is considered a=1 b=2a then 1-2a<0.
1<2a if a=1 then 1<2a.
1<2a if a=1 then 1<2a.
Bujji said:
1 decade ago
How we get the formula. I can't understand, give me the clarification about it.
Kavitha said:
1 decade ago
Please clarify why you are using (1-2a)^2. Why not (2a-1)^2.
Prince said:
1 decade ago
Please explain me these step
=(1 - 2a)^2 + 3a
= (1 - 2a) + 3a
=(1 - 2a)^2 + 3a
= (1 - 2a) + 3a
C.M.Rafeek . Moothedam said:
1 decade ago
I got answer 5a-1 ( 5*0.1039 ) - 1 ie -0.4805
How can 2a-1 and 1-2a be equal ?
How can 2a-1 and 1-2a be equal ?
Sam said:
1 decade ago
Anoop's ans shd be the right one....Thanks Anoop..
Anoop said:
1 decade ago
Ravi because 2a<1, in our formula we have condition of a>b hope getting me correct me if I'm wrong.
Ravi said:
1 decade ago
In the question why he has not taken as 2a-1^2 ?
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers