1
WB JEE 2010
+1
-0.25

If $${(1 - x + {x^2})^n} = {a_0} + {a_1}x + {a_2}{x^2} + \,\,....\,\,{a_{2n}}{x^{2n}}$$, then the value of $${a_0} + {a_2} + {a_4} + \,\,....\,\,{a_{2n}}$$ is

A
$${3^n} + {1 \over 2}$$
B
$${3^n} - {1 \over 2}$$
C
$${{{3^n} - 1} \over 2}$$
D
$${{{3^n} + 1} \over 2}$$
2
WB JEE 2011
+1
-0.25

The coefficient of xn om the expansion of $${{{e^{7x}} + {e^x}} \over {{e^{3x}}}}$$ is

A
$${{{4^{n - 1}} - {{( - 2)}^{n - 1}}} \over {\left| \!{\underline {\, n \,}} \right. }}$$
B
$${{{4^{n - 1}} - {2^{n - 1}}} \over {\left| \!{\underline {\, n \,}} \right. }}$$
C
$${{{4^n} - {2^n}} \over {\left| \!{\underline {\, n \,}} \right. }}$$
D
$${{{4^n} + {{( - 2)}^n}} \over {\left| \!{\underline {\, n \,}} \right. }}$$
3
WB JEE 2011
+1
-0.25

If A and B are coefficients of xn in the expansions of (1 + x)2n and (1 + x)2n $$-$$ 1 respectively, then A/B is equal to

A
4
B
2
C
9
D
6
4
WB JEE 2011
+1
-0.25

If n > 1 is an integer and x $$\ne$$ 0, then (1 + x)n $$-$$ nx $$-$$ 1 is divisible by

A
nx3
B
n3x
C
x
D
nx
EXAM MAP
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