Explanation: 
Another Explanation (5):
সমাধান: ∫cos²(x/2) dx=? 🤔
আমরা জানি, cos(2x) = 2cos²(x) - 1
সুতরাং, cos²(x) = (1 + cos(2x))/2
তাহলে, cos²(x/2) = (1 + cos(x))/2
এখন, ∫cos²(x/2) dx = ∫(1 + cos(x))/2 dx
= ½ ∫(1 + cos(x)) dx
= ½ [∫1 dx + ∫cos(x) dx] 🎉
= ½ [x + sin(x)] + C 🤩
= ½(x + sinx) + C
অতএব, ∫cos²(x/2) dx = ½(x + sinx) + C 🥳