If `(1+x)^5=a_0+a_1x+a2x2+a_3x^3=a_4x^4+a_5x^5,`
then the value of `(a_0-a_2+a_4)^2+(a_1-a_3+a_5)^2`
is equal to
`243`
b. `32`
c. `1`
d. `2^(10)`
A. 243
B. 32
C. 1
D. `2^(10)`
Correct Answer - D
Let (h,k) be the point on the locus. Then by the given conditions,
`(h-a_1)^1+(k-b_1)^2=(h-a_2)^2+(k-b_2)^2`
or `2h(a_1-a_2)+2k(b_1-b_2)+a_2^2+b_2^2-a_1^2=0`
`h(a_1-a_2 )+k(b_1-b_2)+(1)/(2)(a_2^2+b_2^2-a_1^2-b_1^2)=0` .....(1)
Also, since (h,k) lies on the given locus,...
`(1+x+x^(2)+"….."+x^(p))^(n)=a_(0) + a_(1)x+"…."+a_(np)x^(np)`
Differentiating both side w.r.t. , we get
`n(1+x+x^(2)+"……"+x^(p))^(n-1)(1+2x+"….."+px^(p-1))`
`= a_(1)+2a_(2)x+"….."+npa_(np)x^(np-1)`
Now put `x = 1`
`:. a_(1) + 2a_(2) + "......." np a_(np) = n(p+1)^(n-1)(1+2+"...."+p)`
`= (n(p+1)^(n).p)/(2)`
Correct Answer - C
`(c )` Let `d` be common difference of `A.P.impliesd=a_(i)-a_(i-1)`
Now `(1)/(a_(i+1)^(2//3)+a_(i+1)^(1//3)*a_(i)^(1//3)+a_(i)^(2//3))=(a_(i+1)^(1//3)-a_(i)^(1//3))/(a_(i+1)-a_(i))`
`=(1)/(d)[a_(i+1)^(1//3)-a_(i)^(1//3)]`
Thus `sum_(i=1)^(n)(n)/(a_(i+1)^(2//3)+a_(i+1)^(1//3)*a_(i)^(1//3)+a_(i)^(2//3))=(1)/(d)sum_(i=1)^(n-1)(a_(i+1)^(1//3)-a_(i)^(1//3))`
`=(1)/(d)(a_(n)^(1//3)-a_(1)^(1//3))`
`=(1)/(d)((a_(n)-a_(1)))/(a_(n)^(2//3)+a_(n)^(1//3)*a_(1)^(1//3)+a_(1)^(2//3))`
`=((n-1))/(a_(n)^(2//3)+a_(n)^(1//3)*a_(1)^(1//3)+a_(1)^(2//3))`
Correct Answer - A
`(a)` First arrange `12` persons `A_(4),A_(5),….A_(15)` in `"^(15)P_(12)` ways
There remains `3` places. Keep `A_(1)` in the first place and arrange `A_(2)`, `A_(3)` in the remaining two...