why did the alpha went missing in the last step? It should be x cos 2(alpha) +(alpha) cos 2(alpha) - sin 2 (alpha) ln |sin(x+alpha)+C Share with your friends Share 1 S Z answered this alpha cos(alpha) is a constant as it does not have 'x' term, so it is included under 'C'. 3 View Full Answer Ansar Husain Saudagar answered this there is substitution -1 Jaison answered this but how @Ansar Husain Saudagar 0