Tìm nguyên hàm: J=∫(cos3x.cos4x+sin^3 2x)dx3/30Tìm nguyên hàm: J=∫cos3x.cos4x+sin32xdx114sin7x-12sinx-38cos2x+124cos6x+C114sin7x+12sinx+38cos2x+124cos6x+C114sin7x+12sinx-38cos2x+124cos6x+C114sin7x+12sinx-38cos2x-2124cos6x+CGiải thíchChọn C. Ta có : cos3x.cos4x=12cos7x+cosxsin32x=34sin2x-14sin6x Nên suy ra: