Home » If (y alpha frac{1}{x^2}) and (y = 1frac{1}{4}) when x = 4, find the value…

If (y alpha frac{1}{x^2}) and (y = 1frac{1}{4}) when x = 4, find the value…

If (y alpha frac{1}{x^2}) and (y = 1frac{1}{4}) when x = 4, find the value of y when (x = frac{1}{2})
  • A.
    (2frac{1}{2})
  • B.
    5
  • C.
    10
  • D.
    80
Correct Answer: Option D
Explanation

(y propto frac{1}{x^2} Rightarrow y = frac{k}{x^2} Rightarrow k = yx^2\
k = 1frac{1}{4} times 4^2 Rightarrow k=frac{5}{4}times frac{16}{1}=20\
∴y = 20 div left(frac{1}{2}right)^2=20times frac{4}{1}=80)

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