Business Mathematics

251. A triangular matrix can be

  1. Upper triangular
  2. Lower triangular
  3. Both
  4. None
Correct answer: (C)
Both

252. If A = cosØ -sinØ then A+ A = I, if the value of Ø sin Ø cosØ

  1. π/6
  2. π/3
  3. π
  4. 3π/2
Correct answer: (B)
π/3

253. Two matrices A and B are said to be equal if,

  1. A and B are not of same order
  2. A and B are of symmetric order
  3. A and B are of null order
  4. A and B are of same order
Correct answer: (D)
A and B are of same order

254. If the matrix A is both symmetric and skew symmetric, then

  1. A is a diagonal matrix
  2. A is a zero matrix
  3. A is a square matrix
  4. None of these
Correct answer: (B)
A is a zero matrix

255. The area of a triangle whose vertices are ( 3, 8), ( -4, 2) and (5 ,1) is

  1. 63/2
  2. 51/2
  3. 61/2
  4. 55/2
Correct answer: (C)
61/2

256. If area of a triangle is 35sq.units with vertices (2, -6), (5,4) and (k, 4). Then k is

  1. 12
  2. -2
  3. -12, -2
  4. 12, -2
Correct answer: (D)
12, -2

257. Solve -x –y +z = -2
3x +2y -2z =7
x +3y -3z =0

  1. y and z are linearly dependent
  2. x, y, z are independent
  3. x ,y and z are dependent
  4. None of the above
Correct answer: (A)
y and z are linearly dependent

258. The equation ax -3y +5z = 4 is inconsistent for
x –ay +3z =2
9x -7y +8az =0

  1. a =2
  2. a= 3
  3. a =4
  4. a =5
Correct answer: (A)
a =2

259. Solve x +y +z =6 using matrix inversion method
x +2y +3z =14
-x +y –z = -2
a)x=2, y=3, z=1

  1. x=1, y=2, z=3
  2. x=1, y=3,z=5
  3. x=2, y=1, z=3
Correct answer: (B)
x=1, y=3,z=5

260. Solve x -2y +z =1
3x +y -2z =4
y -z =1

  1. x=0, y=-2, z=-3
  2. x=1, y=-1, z=3
  3. x=-2, y=0, z=-3
  4. x=2, y=-1, z=0
Correct answer: (A)
x=0, y=-2, z=-3
Page 26 of 32