WB JEE 2018 | Differentiation Question 30 | Mathematics

WB JEE 2018

MCQ (Single Correct Answer)

-0.25

Let $${f_1}(x) = {e^x}$$, $${f_2}(x) = {e^{{f_1}(x)}}$$, ......, $${f_{n + 1}}(x) = {e^{{f_n}(x)}}$$ for all n $$ \ge $$ 1. Then for any fixed n, $${d \over {dx}}{f_n}(x)$$ is

$${f_n}(x)$$

$${f_n}(x)$$$${f_{n - 1}}(x)$$

$${{f_n}(x)}$$$${f_{n - 1}}(x)$$...$${f_1}(x)$$

$${f_n}(x)$$...$${f_1}(x)$$$${e^x}$$

WB JEE 2018

MCQ (Single Correct Answer)

-0.5

The equation x log x = 3 $$-$$ x

has no root in (1, 3)

has exactly one root in (1, 3)

x log x $$-$$ (3 $$-$$ x) > 0 in [1, 3]

x log x $$-$$ (3 $$-$$ x) < 0 in [1, 3]

WB JEE 2017

MCQ (Single Correct Answer)

-0.25

If $$f(x) = {\log _5}{\log _3}x$$, then f'(e) is equal to

$$e{\log _e}5$$

$$e{\log _e}3$$

$${1 \over {e{{\log }_e}5}}$$

$${1 \over {e{{\log }_e}3}}$$

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