1
WB JEE 2016
MCQ (Single Correct Answer)
+1
-0.25
$$1 + {}^n{C_1}\cos \theta + {}^n{C_2}\cos 2\theta + ... + {}^n{C_n}\cos n\theta $$ equals
A
$${\left( {2\cos {\theta \over 2}} \right)^n}\cos {{n\theta } \over 2}$$
B
$$2{\cos ^2}{{n\theta } \over 2}$$
C
$$2{\cos ^{2n}}{\theta \over 2}$$
D
$${\left( {2{{\cos }^2}{\theta \over 2}} \right)^n}$$
2
WB JEE 2016
MCQ (Single Correct Answer)
+1
-0.25
If x, y and z are greater than 1, then the value of $$\left| {\matrix{ 1 & {{{\log }_x}y} & {{{\log }_x}z} \cr {{{\log }_y}x} & 1 & {{{\log }_y}z} \cr {{{\log }_z}x} & {{{\log }_z}y} & 1 \cr } } \right|$$ is
A
log x . log y . log z
B
log x + log y + log z
C
0
D
1 $$-$$ {(log x) . (log y) . (log z)}
3
WB JEE 2016
MCQ (Single Correct Answer)
+1
-0.25
Let A be a 3 $$ \times $$ 3 matrix and B be its adjoint matrix. If | B | = 64, then | A | is equal to
A
$$ \pm $$2
B
$$ \pm $$4
C
$$ \pm $$8
D
$$ \pm $$12
4
WB JEE 2016
MCQ (Single Correct Answer)
+1
-0.25
Let $$Q = \left[ {\matrix{ {\cos {\pi \over 4}} & { - \sin {\pi \over 4}} \cr {\sin {\pi \over 4}} & {\cos {\pi \over 4}} \cr } } \right]$$ and $$x = \left[ {\matrix{ {{1 \over {\sqrt 2 }}} \cr {{1 \over {\sqrt 2 }}} \cr } } \right]$$, then Q3x is equal to
A
$$\left( {\matrix{ 0 \cr 1 \cr } } \right)$$
B
$$\left( {\matrix{ { - {1 \over {\sqrt 2 }}} \cr {{1 \over {\sqrt 2 }}} \cr } } \right)$$
C
$$\left( {\matrix{ { - 1} \cr 0 \cr } } \right)$$
D
$$\left( {\matrix{ { - {1 \over {\sqrt 2 }}} \cr { - {1 \over {\sqrt 2 }}} \cr } } \right)$$
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12