2020 · Q26
If x varies as y, then which of the following is/are correct?
- 1x² + y² varies as x² − y²
- 2x/y² varies inversely as y
- 3ⁿ√(x²y) varies as ²ⁿ√(x⁴y²)
Select the correct answer using the code given below:
Elementary MathematicsRatio and Proportion
- A1 and 2 only
- B2 and 3 only
- C3 only
- D1, 2 and 3
Explanation
With x = ky: (x^2+y^2)/(x^2-y^2) = (k^2+1)/(k^2-1), a constant, so 1 is true. x/y^2 = k/y varies inversely as y, so 2 is true. And the 2n-th root of x^4*y^2 equals (x^2*y)^(1/n), the n-th root of x^2*y, so 3 is true. All three - option (D).