If `A={1,2}` then find `n[p(A)]`

If two natural numbers r and s are drawn one at a time, without replacement from the set S={1,2,3,….n}, then find P (rlep//slep) where p in S.

If X~B(n,p),mu=20,sigma^(2)=10 , then find n and p.

Let p be a non singular matrix, and I + P + p^2 + ... + p^n = 0, then find p^-1 .

If O is the origin, O P=3 with direction ratios -1,2,a n d-2, then find the coordinates of Pdot

If P(n ,4)=20xxP(n ,2), then find the value of n

If S_n=n P+(n(n-1))/2Q ,w h e r eS_n denotes the sum of the first n terms of an A.P., then find the common difference.

If S_n=n P+(n(n-1))/2Q ,w h e r eS_n denotes the sum of the first n terms of an A.P., then find the common difference.

If S_n=n P+(n(n-1))/2Q ,w h e r eS_n denotes the sum of the first n terms of an A.P., then find the common difference.

If P(n ,4)=20 x P(n ,2),find n.

If "^(2n+1)P_(n-1):^(2n-1)P_n=3:5, then find the value of n .