Processing math: 8%




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26.

 Let a1,a2,a3.......,a100 be an arithmetic progression with  a1=3  and 

Sp=pi=1ai,1p100 for any integer n with 1n20 , let m=5n, If SmSn does not depend  on n, then a2 is 


A) 3

B) 9

C) 4

D) 5



27.

The positive integer value of n > 3 satisfying the equation

\frac{1}{\sin\left(\frac{\pi}{n}\right)}=\frac{1}{\sin\left(\frac{2\pi}{n}\right)}+\frac{1}{\sin\left(\frac{3\pi}{n}\right)} is 


A) 5

B) 4

C) 7

D) 3



28.

Let a, b and c be three real numbers satisfying [a b c] \begin{bmatrix}1 & 9 &7 \\8 & 2&7 \\7&3&7 \end{bmatrix}=\begin{bmatrix}0 & 0 &0 \end{bmatrix}

Let b=6, with  a and c satisfying Eq. (E). If \alpha and \beta are the roots of the quadratic  equation  ax^{2}+bx+c=0 

 then  \sum_{n=0}^{\infty}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)^{n} is 


A) 6

B) 7

C) \frac{6}{7}

D) \infty



29.

Let a, b and c be three real numbers satisfying [a b c] \begin{bmatrix}1 & 9 &7 \\8 & 2&7 \\7&3&7 \end{bmatrix}=\begin{bmatrix}0 & 0 &0 \end{bmatrix}

 Let \omega  be a solution of   x^{3}-1=0  with  Im (\omega) >0.If a=2  with b and c satisfying Eq (E). then the value of \frac{3}{\omega^{\alpha}}+\frac{1}{\omega^{b}}+\frac{3}{\omega^{c}}


A) -2

B) 2

C) 3

D) -3



30.

Let a, b and c be three real numbers satisfying [a b c]  \begin{bmatrix}1 & 9 &7 \\8 & 2&7 \\7&3&7 \end{bmatrix}=\begin{bmatrix}0 & 0 &0 \end{bmatrix}

If the point P(a, b, c), with reference to Eq. (E), lies on the plane 2x + y +z = 1, then the value of 7 a + b + c is


A) 0

B) 12

C) 7

D) 6



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