If x varies directly as y, then which of the following is/are correct ? I. (x^2 + y^2) varies directly as y^2. II. \left(\frac{x^3}{y^4}\right) varies directly as y. Select the answer using the code given below :
- A. I only ✓
- B. II only
- C. Both I and II
- D. Neither I nor II
Correct Answer: A. I only
Explanation
Since x = ky, for I: x^2 + y^2 = (k^2 + 1)y^2, meaning it varies directly as y^2 (True). For II: x^3 / y^4 = k^3 y^3 / y^4 = k^3 / y, meaning it varies inversely as y (False).
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