Question

求(x+1)(x+2)(x+3)(x+4)(x+5)的展开式

Answer 1

x+1)*(x+2)=x^2+3x+2

(x+1)*(x+2)*(x+3)=x^3+6x^2+11x+6

(x+1)*(x+2)*(x+3)*(x+4)=x^4+10x^3+35x^2+50x+24

(x+1)(x+2)(x+3)(x+4)(x+5)=x^5+15x^4+50x^3+225x^2+274x+120