The harmonic mean of $\frac{a}{1-ab}$ and $\frac{a}{1+ab}$ is

Important Questions on Sequences and Series

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IMPORTANT

Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 19

Geometric mean of $7, 7^2, 7^3........7^n$ is -

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IMPORTANT

Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 20

The sum of series, $6+66+666+........$ upto $n$ term is -

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IMPORTANT

Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 21

If $b^2, a^2, c^2$ are in $\mathrm{A}.\mathrm{P}.,$ then $a+b, b+c, c+a$ will be in

EASY

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Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 22

If three positive real numbers $a,b,c$ are in $\mathrm{AP}$, such that $abc=4,$ then the minimum value of $b$ is

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IMPORTANT

Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 23

If $\frac{1}{b-a}+\frac{1}{b-c}=\frac{1}{a}+\frac{1}{c},$ then $a,b,c$ are in

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Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 24

Let $a+b+c=10, a, b, c>0$, then the maximum value of $a^2 b^3 c^5$ is -

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IMPORTANT

Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 25

Let $2x+3y+4z=9, x, y, z>0$  then the maximum value of ${\left(1+x\right)}^2 {\left(2+y\right)}^3 {\left(4+z\right)}^4$ is -

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IMPORTANT

Gamma Question Bank for Engineering Mathematics>Chapter 4 - Sequences and Series>EXERCISE>Q 26

The sum of $1+\frac{2}{5}+\frac{3}{5^2}+\frac{4}{5^3}+....$ up to $n$ terms is