Given that y varies inversely as the square of x. If x = 3 when y = 100, find the equation connecting x and y.
-
A.
(yx^2 = 300) -
B.
(yx^2 = 900) -
C.
y = (frac{100x}{9}) -
D.
(y = 900x^2)
Correct Answer: Option B
Explanation
Y (alpha frac{1}{x^2} rightarrow y = frac{k}{x^2})
If x = 3 and y = 100,
then, (frac{100}{1} = frac{k}{3^2})
(frac{100}{1} = frac{k}{9})
k = 100 x 9 = 900
Substitute 900 for k in
y = (frac{k}{x^2}); y = (frac{900}{x^2})
= (yx^2 = 900)