1.∫（3x^4-2x+1）dx
=∫3x^4 dx -∫2xdx+∫dx
=(3/5)x^5-x^2+x+C
C为任意常数
2.∫cos(2-3x)dx
=-(1/3)∫cos(2-3x)d(2-3x)
=-(1/3)sin(2-3x)+C
=(1/3)sin(3x-2)+C
C为任意常数
3.∫(2x+3)^7dx
=(1/2)∫(2x+3)^7d(2x+3)
=(1/16)(2x+3)^8+C
C为任意常数