<p>This question was on the May 2007 test:</p>
<p>If x does not equal 0 and x is inversely proportional to y, which of the following is directly proportional to 1/x^2?</p>
<p>The answer is y^2.</p>
<p>Anyone know how to do this? I've looked for the explanation online but couldn't find any clear explanations.</p>
<p>I don’t know how to get the proportionality sign so permit me to use “~” instead.
x~1/y
making y the subject in the proportionality,
y~1/x…equation 1.
a variable being proportional to 1/x^2 is automatically directly proportional to 1^2/x^2.
At this point you can tell that you are just squaring equation 1.
therefore y^2 is directly proportional to 1/x^2.</p>