Mathematics for IGCSE & O level - Proportion (Section 1 - No. 3)
Given that *y* varies inversely as the square root of *x*, if *x* increases by a factor of 4, how does *y* change?
y increases by a factor of 2
y decreases by a factor of 2
y increases by a factor of 4
y decreases by a factor of 4
Giải thích
Since y = k/sqrt(x), if x becomes 4x, then y becomes k/sqrt(4x) = k/(2*sqrt(x)), so y is halved.