If {\cos ^{ - 1}}x - {\cos ^{ - 1}}{y \over 2} = \alpha,where –1 ≤ x ≤ 1, – 2 ≤ y ≤ 2, x ≤{y \over 2}
, then for all x, y, 4x2
– 4xy cos α + y2
is equal
to :
A group of students comprises of 5 boys and n girls. If the number of ways, in which a team of 3 students can
randomly be selected from this group such that there is at least one boy and at least one girl in each team, is
1750, then n is equal to :
The number of ways of choosing 10 objects out of 31 objects of which 10 are identical and the remaining 21
are distinct, is :
Mathematicspermutations-and-combinations2019easy
Suppose that 20 pillars of the same height have been erected along the boundary of a circular stadium. If the
top of each pillar has been connected by beams with the top of all its non-adjacent pillars, then the total
number of beams is :
A committee of 11 members is to be formed from
8 males and 5 females. If m is the number of ways
the committee is formed with at least 6 males and
n is the number of ways the committee is formed
with at least 3 females, then :
All possible numbers are formed using the digits
1, 1, 2, 2, 2, 2, 3, 4, 4 taken all at a time. The number
of such numbers in which the odd digits occupy
even places is :