Saved Bookmarks
| 1. |
If the coefficient of x in the expansion of `prod_(r=1)^(110)(1+rx)` is `lambda(1+110)(1+10+10^(2))`, then the value of ` lambda` is |
|
Answer» `:.sum_(r=1)^(110)(1+rx)=(1+x)(1+2x)(1+3x)"...."(1+110x)` `=1^(100)+(z+2x+3x+"...."+110x)1^(109)+"....."` So, coefficient of x in `sum_(r=1)^(110)(1+rx)=(1+2+3+"......"+110)=(110xx111)/(2)=55xx111=6105` Now, `lambda(1+10)(1+10+10^(2))=lambda(11)(111)` `implieslambda(11)(111)=6105 implies lambda=5`. |
|