diffrentiate cosx.cos2x.cos3x using repeated application of product rule..plss be fast..!!!!!!!!urgent!!!!!!!! Share with your friends Share 2 Ajanta Trivedi answered this ddx(cosxcos2xcos3x)=(ddxcosx)(cos2xcos3x)+cosxddx(cos2xcos3x)=-sinxcos2xcos3x+cosx*[(ddxcos2x)cos3x+cos2x(ddxcos3x)]=-sinxcos2xcos3x+cosx*[-2sin2xcos3x+cos2x*(-3sin3x)]=-sinxcos2xcos3x-2sin2xcosxcos3x-3cosxcos2xsin3x hope this helps you 3 View Full Answer
