1/(x+1) + 1/(x+1)(x+2) + 1/(x+2)(x+3) + 1/(x+3)(x+4) + 1/(x+4)(x+5) + 1/(x+5)

2 bình luận về “1/(x+1) + 1/(x+1)(x+2) + 1/(x+2)(x+3) + 1/(x+3)(x+4) + 1/(x+4)(x+5) + 1/(x+5)”

1. 1/(x+1) + 1/((x+1)(x+2)) + 1/((x+2)(x+3)) + 1/((x+3)(x+4)) + 1/((x+4)(x+5)) + 1/(x+5)

   =1/(x+1) + 1/(x+1)-1/(x+2) + 1/(x+2)-1/(x+3) + 1/(x+3)-1/(x+4) + 1/(x+4)-1/(x+5) + 1/(x+5)

   =2/(x+1)

   Trả lời
2. 1/(x + 1) + 1/((x+1)(x+2)) + 1/((x+2)(x+3)) + 1/((x+3)(x+4)) + 1/((x+4)(x+5)) + 1/(x + 5)

   ĐK : x \ne -1 ; x\ne -2 ; x\ne-3;x\ne-4;x\ne-5

   = 1/(x + 1) + 1/(x + 1) – 1/(x + 2) + 1/(x + 2) – 1/(x + 3) + 1/(x + 3) – 1/(x + 4) + 1/(x + 4) – 1/(x + 5) + 1/(x + 5)

   = 2/(x + 1)

   Trả lời