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.
Jessi said:
1 decade ago
x = 3*2+1/3-1 = 9+1/2 = 10/2 = 5.
y = 3*2-1/3+1 = 9-1/4 = 8/4 = 2.
The use the formula x2+y2 = 5*2+2*2 = 10+4 = 14.
y = 3*2-1/3+1 = 9-1/4 = 8/4 = 2.
The use the formula x2+y2 = 5*2+2*2 = 10+4 = 14.
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.
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.
Bhushan said:
6 years ago
x2 + y2 = (2 + √3)2 + (2 - √3)2.
= (4+2*2*√3+3) + (4 - 2*2*√3+3),
= (4+3) + (4+3),
= 2(4+3).
= (4+2*2*√3+3) + (4 - 2*2*√3+3),
= (4+3) + (4+3),
= 2(4+3).
(5)
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.
Ram said:
8 years ago
(2 + 3) 2 + (2 - 3) 2.
Explanation:
7+4root3+3+4-root3+3.
+4root3-4root3 cancel.
After that,
4+3+4+3 = 14.
Explanation:
7+4root3+3+4-root3+3.
+4root3-4root3 cancel.
After that,
4+3+4+3 = 14.
Mohit said:
1 decade ago
Can any buddy help me to understand this problem solution in a simple and detail way.
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)
Tank Mayur B. said:
1 decade ago
This is wrong solution .
because: ((a+b)/(a-b))*((a+b)/(a+b))=(a+b)2/(a2 + b2)
because: ((a+b)/(a-b))*((a+b)/(a+b))=(a+b)2/(a2 + b2)
Jay said:
1 decade ago
Who got 2 as the correct answer? That's what I had and I'm sure I am right!
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