Only when the roots of the characteristic equation are imaginary do you typically express the homogeneous solution as a sinusoid. For example, if the...
I think to begin, I would imagine that Randi has the cards arranged in the same order she will seek them...for example suppose she will seek them in...
I was getting ready to reply that you need another initial condition, but you've fixed that. Also, I moved the thread to "Differential Equations" as...
That's where the sketch of the region $D$ comes in...for example when using horizontal strips, we see they are bounded on the left by the line $x=0$...
Head of Mathematics Department, I.E.S. Sta Teresa, Madrid.
Prof. of Mathematical Methods, Univ. Alfonso X El Sabio, Madrid.
(Up until the 2008/2009 academic year. I am now devoted to investigation).