1. The problem statement, all variables and given/known data I made a thread last week where I had a reasonable idea what was going on in 2 problems last week this week I have 2 problems where i have NO idea where to start. Show that the ellipse x2 +2 y2 =2 and the hyperbola 2 x2 - 2 y2 =1 intersect at right angles. What is the first time after 3 o'clock that the hands of the clock are together? 2. Relevant equations 3. The attempt at a solution 1st problem, all I know is that perpendicular lines have similar slopes( dunno how to explain , for example 1 line has slope of 4 , perpendicular has to have a slope of -1/4). but why does that matter? these are not lines so slopes shouldnt even matter at all, should I use implicit differentiation? even if I do, what for? 2nd problem, dunno how to start, cant even draw a diagram , t.t help!