<p>Quick question...I've been doing the questions in the 22 reals prep book, and understand them all but this stupid ellipse problem. Can you help me get this?</p>
<p>Here's the question:</p>
<p>What is the length of the major axis of the ellipse whose equation is 60x^2+30y^2=150?</p>
<p>a) 1.26
b) 2.50
c) 3.16
d)4.47
e) 5.00</p>
<p>The answer is d. Thanks!</p>
<p>Major axis is obviously longer one of the two axis of the ellipses
First, you need to set right side of the equation to 1, so just divide both sides by 150. Then you have x^2/(150/60)+ y^2/(150/30)=1 Here, you have the form x^2/a^2 + y^2/b^2 =1, in which a and b are half of the lengths of major and minor axis. So, a=1.58 and b=2.236. Obviously b is bigger so b is major axis, so just multiply that by 2 to get the whole length of the major axis(since b was only half the length of major axis).</p>
<p>I'm not sure if that helped any, but i hope it did.</p>
<p>Yeah, thanks!</p>
<p>I just took that test, it's very silly</p>