COMEDK 2020

A group (G *) has 10 elements. The minimum number of elements of G, which are their own inverses is

A graph G has m vertices of odd degree and ‘n’
vertices of even degree. Then which of the
following statements is necessarily true?

Which of the following is not a group with
respect to the given operation?

The coordinates of the foot of the perpendicular drawn from the point (3, 4) on the line \(2x+y-7=0\) is

A vector perpendicular to the plane containing the points \(A(1, - 1,2),B(2,0, - 1),C(0,2,1)\) is

If \(\sin 3\theta = \sin \theta\), how many solutions exist such that \(- 2\pi < \theta < 2\pi\)?

\({\sin ^2}17.5^\circ + \sin 72.5^\circ\) is equal to

If a and b are vectors such that \(|a + b|=|a-b|\), then the angle between a and b is

If \(a = 2\widehat i + 3\widehat j - \widehat k,b = \widehat i + 2\widehat j - 5\widehat k,c = 3\widehat i + 5\widehat j - \widehat k\), then a vector perpendicular to a and in the plane containing b and c is

OA and BO are two vectors of magnitudes 5 and 6 respectively. If \(\angle BOA=60^\circ\), then OA . OB is equal to