JEE Main 2021 (Online) 27th August Evening Shift | Sequences and Series Question 61 | Mathematics

JEE Main 2021 (Online) 27th August Evening Shift

MCQ (Single Correct Answer)

-1

If 0 < x < 1 and $$y = {1 \over 2}{x^2} + {2 \over 3}{x^3} + {3 \over 4}{x^4} + ....$$, then the value of e^{1 + y} at $$x = {1 \over 2}$$ is :

$${1 \over 2}{e^2}$$

$${1 \over 2}\sqrt e $$

2e²

JEE Main 2021 (Online) 27th August Morning Shift

MCQ (Single Correct Answer)

-1

If 0 < x < 1, then $${3 \over 2}{x^2} + {5 \over 3}{x^3} + {7 \over 4}{x^4} + .....$$, is equal to :

$$x\left( {{{1 + x} \over {1 - x}}} \right) + {\log _e}(1 - x)$$

$$x\left( {{{1 - x} \over {1 + x}}} \right) + {\log _e}(1 - x)$$

$${{1 - x} \over {1 + x}} + {\log _e}(1 - x)$$

$${{1 + x} \over {1 - x}} + {\log _e}(1 - x)$$

JEE Main 2021 (Online) 27th August Morning Shift

MCQ (Single Correct Answer)

-1

If for x, y $$\in$$ R, x > 0, y = log₁₀x + log₁₀x^1/3 + log₁₀x^1/9 + ...... upto $$\infty$$ terms

and $${{2 + 4 + 6 + .... + 2y} \over {3 + 6 + 9 + ..... + 3y}} = {4 \over {{{\log }_{10}}x}}$$, then the ordered pair (x, y) is equal to :

(10⁶, 6)

(10⁴, 6)

(10², 3)

(10⁶, 9)

JEE Main 2021 (Online) 26th August Morning Shift

MCQ (Single Correct Answer)

-1

The sum of the series

$${1 \over {x + 1}} + {2 \over {{x^2} + 1}} + {{{2^2}} \over {{x^4} + 1}} + ...... + {{{2^{100}}} \over {{x^{{2^{100}}}} + 1}}$$ when x = 2 is :

$$1 + {{{2^{101}}} \over {{4^{101}} - 1}}$$

$$1 + {{{2^{100}}} \over {{4^{101}} - 1}}$$

$$1 - {{{2^{100}}} \over {{4^{100}} - 1}}$$

$$1 - {{{2^{101}}} \over {{2^{400}} - 1}}$$

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