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12th Standard Maths English Medium Free Online Test 1 Mark Questions 2020 - Part Nine

12th Standard

    Reg.No. :
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Maths

Time : 00:10:00 Hrs
Total Marks : 10

    Answer all the questions

    10 x 1 = 10
  1. If A = \(\left[ \begin{matrix} 3 & -3 & 4 \\ 2 & -3 & 4 \\ 0 & -1 & 1 \end{matrix} \right] \), then adj(adj A) is

    (a)

    \(\left[ \begin{matrix} 3 & -3 & 4 \\ 2 & -3 & 4 \\ 0 & -1 & 1 \end{matrix} \right] \)

    (b)

    \(\left[ \begin{matrix} 6 & -6 & 8 \\ 4 & -6 & 8 \\ 0 & -2 & 2 \end{matrix} \right] \)

    (c)

    \(\left[ \begin{matrix} -3 & 3 & -4 \\ -2 & 3 & -4 \\ 0 & 1 & -1 \end{matrix} \right] \)

    (d)

    \(\left[ \begin{matrix} 3 & -3 & 4 \\ 0 & -1 & 1 \\ 2 & -3 & 4 \end{matrix} \right] \)

  2. If \(\omega =cis\cfrac { 2\pi }{ 3 } \), then the number of distinct roots of \(\left| \begin{matrix} z+1 & \omega & { \omega }^{ 2 } \\ \omega & z+{ \omega }^{ 2 } & 1 \\ { \omega }^{ 2 } & 1 & z+\omega \end{matrix} \right| \)=0

    (a)

    1

    (b)

    2

    (c)

    3

    (d)

    4

  3. The equation \(\tan ^{-1} x-\cot ^{-1} x=\tan ^{-1}\left(\frac{1}{\sqrt{3}}\right)\)has

    (a)

    no solution

    (b)

    unique solution

    (c)

    two solutions

    (d)

    infinite number of solutions

  4. In a \(\Delta ABC\)  if C is a right angle, then  \({ tan }^{ -1 }\left( \frac { a }{ b+c } \right) +{ tan }^{ -1 }\left( \frac { b }{ c+a } \right) =\) ________

    (a)

    \(\frac { \pi }{ 3 } \)

    (b)

    \(\frac { \pi }{ 4 } \)

    (c)

    \(\frac { 5\pi }{ 2 } \)

    (d)

    \(\frac { \pi }{ 6 } \)

  5. If x = r cos θ, y = r sin, then \(\frac { \partial r }{ \partial x } \) = ....................

    (a)

    sec θ

    (b)

    sin θ

    (c)

    cos θ

    (d)

    cosec θ

  6. If is a homogeneous function of x and y of degree n, then \(x\frac { { \partial }^{ 2 }u }{ \partial { x }^{ 2 } } +y\frac { { \partial }^{ 2 }u }{ \partial x\partial y } \) = ...... \(\frac { { \partial }u }{ \partial { x } } \)

    (a)

    n

    (b)

    0

    (c)

    1

    (d)

    n - 1

  7. The area enclosed by the curve y2 = 4x, the x-axis and its latus rectum is ________ sq.units.

    (a)

    \(\frac23\)

    (b)

    \(\frac43\)

    (c)

    \(\frac83\)

    (d)

    \(\frac{16}{3}\)

  8. P is the amount of certain substance left in after time t. If the rate of evaporation of the substance is proportional to the amount remaining, then

    (a)

    P = Cekt

    (b)

    P = Ce-kt

    (c)

    P = Ckt

    (d)

    Pt = C

  9. The solution of log \(\left( \frac { dy }{ dx } \right) \) = ax + by is______.

    (a)

    \(\frac { { e }^{ ax } }{ a } +\frac { { e }^{ -by } }{ b } +c=0\)

    (b)

    aeax- be-by + c = 0

    (c)

    ae+ be= k

    (d)

    beax + ae-by = k

  10. If a * b = a2b2 - ab then 3 * (1 * 1)

    (a)

    0

    (b)

    1

    (c)

    2

    (d)

    4

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