waecmaths question:
Given that y varies inversely as the square of x. If x =3 when y =200. Find the equation connecting x and y
Option A:
$y{{x}^{2}}=300$
Option B:
$y{{x}^{2}}=900$
Option C:
$y=\frac{100x}{9}$
Option D:
$y=900{{x}^{2}}$
waecmaths solution:
$\begin{align}
& y\propto \frac{1}{{{x}^{2}}} \\
& y=\frac{k}{{{x}^{2}}}\left| k=proportionality constant\text{ } \right. \\
& 100=\frac{k}{{{3}^{2}}} \\
& k=900 \\
& \text{The relationship will} \\
& y=\frac{900}{{{x}^{2}}} \\
& y{{x}^{2}}=900 \\
\end{align}$
maths year:
maths topics: