Processing math: 100%
Home / Aptitude Tests / Mathematics / Let = \(\begin{pmatr...
Let = (1001) p = \...

Let = (1001) p = (2345) Q = (u4+u2vv) be 2 x 2 matrices such that PQ = 1. Find (u, v)

A.

(-52 - 1)

B.

(-52 - 32)

C.

(-56 - 1)

D.

(52 - 32)

Correct answer is A

PQ = (2345)(u4+u2vv)

= ((2u6v2(4+u)+3v)4u10v4(4+u)+5v)

= (1001)

2u - 6v = 1.....(i)

4u - 10v = 0.......(ii)

2(4 + u) + 3v = 0......(iii)

4(4 + u) + 5v = 1......(iv)

2u - 6v = 1 .....(i) x 2

4u - 10v = 0......(ii) x 1

4u - 12v = 0-4u - 10v = 0

-2v = 2 = v = -1

2u - 6(-1) = 1 = 2u = 5

u = -52

∴ (U, V) = (-52 - 1)