In Z, the set of all integers, the inverse of - 7 w.r.t. * defined by ab = a + b + 7 for all a,b Z is
- 14
7
14
- 7
Assuming that the sums and products given below are defined which ofthe following is not true for matrices?
AB = AC does not imply B = C
A + B = B + A
(AB)' = B'A'
AB = 0 implies A = 0 or B = 0
A.
AB = AC does not imply B = C
As (b), (c), (d) are always true but (a) show
AB = AC
The rate ofchange of the surface area ofthe sphere of radius r when the radius is increasing at the rate of 2 cm/sec is proportional to
r2
r