Need help solving number 48 please

Using a Product-to-Sum Formula In Exercises 43, 44, 45, 46, 47, and 48, find the indefinite integral. 43 . cos 2x cos ba da Answer + 44. cos 50 cos 30 de 45. sin 2t cos It dt Answer * 46. sin 8x cos 7x dx 47. sin 0 sin 30 de Answer + 48. sin 5x sin 4x dx