Can someone please explain how to get from step 1 to step 2. Im not sure what formula the calculator is plugging it into and getting that integral

Hide steps Problem: sin?(3x) cos(4x) da Apply product-to-sum formulas: sin(x) sin(y) = (cos(y - x) - cos(y + x)), sin (x) = = (1 - cos(2x)), cos(x) cos(y) = (cos(y + x) + cos(y - x)), cos?(x) = (cos(2x) + 1), sin(x) cos(y) = (sin(y + x) - sin(y - x)), cos(x) sin(x) = - sin(2x) cos(10x) - 2 cos(4x) + cos(2x)