∫cos(3x+1)dx
=(1/3)∫cos(3x+1)d3x
=(1/3)∫cos(3x+1)d(3x+1)
=(1/3)∫d(sin(3x+1))
=(1/3)sin(3x+1)+C∫(x-1)(x3-1)dx是x的3次方也是不定的∫(x-1)(x³-1)dx=∫(x⁴-x-x³+1)dx=(x^5)/5-x²/2-x⁴/4+x+C