If x=sint,y=sinkt, then (1−x2)y2−xy1=
dydx=dydtdxdt=kcos ktcos t d2ydx2=ddt(dydx)dtdx=k(−ksin k.tcos t+sin t.cos ktcos2t)1cos t y2cos2t=−k2sinkt+sintcosktcost(−k) (1−x2)y2=−k2y+xy1 (1−x2)y2−xy1=−k2y