If the vectors `ahat(i)+hat(j)+hat(k), hat(i)+bhat(j)+hat(k), hat(i)+hat(j)+chat(k), (anebnec)` are coplanar, then `(1)/(1-a)+(1)/(1-b)+(1)/(1-c)=`

Options

A. 0
B. 1
C. -1
D. 2

Answer

A, C

Explanation

`I=underset(1)overset(2)(int)(e^(x))/(x)dx`
`f(x)=(e^(x))/(x),f'(x)=((x-1)e^(x))/(x^(2))gt 0 [AA x in (1,2)]`
`rarrIgtAr.[ACDE]`
` I gt e xx 1 implies I gt e ....(1)`
`rarr I lt "Area of trapezium ABCDE"`
`Ilt (1)/(2)(1)[e+(e^(2))/(2)]`
`I lt (e)/(2)+(e^(2))/(4)" ".......(2)`
`(I gt 3+(e)/(2))` is false from (2)