JAMB - Mathematics (1982 - No. 39)
A variable y is inversely proportional to x2, when y = 10, x = 2. What is y when x = 10?
2
4
100
0.4
0.1
설명
y \(\alpha\) \(\frac{1}{x^2}\)
y = \(\frac{k}{x^2}\)
k = x2y
= (2)2 x 10
= 40
y = \(\frac{40}{x^2}\)
= \(\frac{40}{(10)^2}\)
= \(\frac{40}{100}\)
= 0.4
y = \(\frac{k}{x^2}\)
k = x2y
= (2)2 x 10
= 40
y = \(\frac{40}{x^2}\)
= \(\frac{40}{(10)^2}\)
= \(\frac{40}{100}\)
= 0.4