Aptitude - Square Root and Cube Root - Discussion
Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 7)
7.
| If x = | 3 + 1 | and y = | 3 - 1 | , then the value of (x2 + y2) is: |
| 3 - 1 | 3 + 1 |
Answer: Option
Explanation:
| x = | (3 + 1) | x | (3 + 1) | = | (3 + 1)2 | = | 3 + 1 + 23 | = 2 + 3. |
| (3 - 1) | (3 + 1) | (3 - 1) | 2 |
| y = | (3 - 1) | x | (3 - 1) | = | (3 - 1)2 | = | 3 + 1 - 23 | = 2 - 3. |
| (3 + 1) | (3 - 1) | (3 - 1) | 2 |
x2 + y2 = (2 + 3)2 + (2 - 3)2
= 2(4 + 3)
= 14
Discussion:
45 comments Page 2 of 5.
Shudipta Baruah said:
9 years ago
This is correct: 14
x = (3 + 1) x (3 + 1) = (3 + 1)2
= 3 + 1 + 23 = 2 + 3.
(3 - 1) (3 + 1) (3 - 1) 2.
y = (3 - 1) x (3 - 1) = (3 - 1)2 = 3 + 1 - 23 = 2 - 3.
(3 + 1) (3 - 1) (3 - 1) 2,
x2 + y2 = (2 + 3)2 + (2 - 3)2,
= 2(4 + 3),
= 14.
x = (3 + 1) x (3 + 1) = (3 + 1)2
= 3 + 1 + 23 = 2 + 3.
(3 - 1) (3 + 1) (3 - 1) 2.
y = (3 - 1) x (3 - 1) = (3 - 1)2 = 3 + 1 - 23 = 2 - 3.
(3 + 1) (3 - 1) (3 - 1) 2,
x2 + y2 = (2 + 3)2 + (2 - 3)2,
= 2(4 + 3),
= 14.
Pranay Patil said:
9 years ago
Can anyone explain me why can't we solve x and y individually to get x^2 = 4 and y^2 = 1/4? So to get x^2 +y^2 = 17/4.
Deepak Gehlot said:
9 years ago
This is wrong solution.
KARTHI said:
9 years ago
How to solve this problem logically?
Skrn said:
10 years ago
The question I got didn't have a root 3 value. Thanks.
Bhavesh Kirange said:
10 years ago
@Jayshree.
3+1 = 4 so it becomes, 4+2√3/2.
Here take 2 common and it comes (2(2+√3))/2 = 2+√3.
3+1 = 4 so it becomes, 4+2√3/2.
Here take 2 common and it comes (2(2+√3))/2 = 2+√3.
Jayshree said:
10 years ago
Hello, I just didn't understand how is 3+1+2√3/2 = 2+√3.
Please explain.
Please explain.
(1)
Animesh said:
10 years ago
Use "(x^2+y^2) = (x+y)^2-2xy".
Here xy = 1;
Here just put the values of x and y and you can get the answer which is 14.
Here xy = 1;
Here just put the values of x and y and you can get the answer which is 14.
Abhirup said:
10 years ago
The answer to this question is correct. They have just step-jumped.
Gopi said:
1 decade ago
The answer is to its formula (x+y)^2=x^2+y^2+2xy.
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