Solve for x,

${4^x} – {3^{x – \frac{1}{2}}} = {3^{x + \frac{1}{2}}} – {2^{2\left( {x – \frac{1}{2}} \right)}}$

We have, ${2^{2x}} + \frac{{{2^{2x}}}}{2} = {3^x}\sqrt 3 + \frac{{{3^x}}}{{\sqrt 3 }}$

$ \Rightarrow \frac{3}{2}{.2^{2x}} = \frac{4}{{\sqrt 3 }}{.3^x}$

$ \Rightarrow \frac{{{2^{2x}}}}{8} = \frac{{{3^x}}}{{3\sqrt 3 }}$

$ \Rightarrow {2^{2x – 3}} = {3^{x – \frac{3}{2}}}$

$ \Rightarrow {2^{2\left( {x – \frac{3}{2}} \right)}} = {3^{x – \frac{3}{2}}}$

$ \Rightarrow {4^{x – \frac{3}{2}}} = {3^{x – \frac{3}{2}}}$

The above is only possible if $x – \frac{3}{2} = 0$ or $x=\frac {3}{2}$.

${x^2}f(x) + f\left( {\frac{1}{x}} \right) = 0,x \ne 0$

$I = \int\limits_{\tan \alpha }^{\cot \alpha } {f(x)dx} = ?$

We have, $f(x) = – \frac{1}{{{x^2}}}f\left( {\frac{1}{x}} \right)$

$\therefore I = \int\limits_{\tan \alpha }^{\cot \alpha } { – \frac{1}{{{x^2}}}f\left( {\frac{1}{x}} \right)dx} $

Let, $\frac{1}{x} = t$

$ \Rightarrow – \frac{1}{{{x^2}}}dx = dt$

$\therefore I = \int\limits_{\cot \alpha }^{\tan \alpha } {f(t)dt} =-I $

$ \Rightarrow I = 0$

Find $f(x)$ such that,

$f(x) + f\left( {\frac{1}{x}} \right) + 3f( – x) = x$

$x \to \frac{1}{x}$ in the original equation yields,

$f\left( {\frac{1}{x}} \right) + f(x) + 3f\left( { – \frac{1}{x}} \right) = \frac{1}{x}$ ……..(A)

Original equation – (A) yields,

$3f( – x) – 3f\left( { – \frac{1}{x}} \right) = x – \frac{1}{x}$ Continue reading Find $f(x)$ such that,

$f(x) + f\left( {\frac{1}{x}} \right) + 3f( – x) = x$

$\begin{array}{l}f\left( {x + \frac{1}{x} + 4} \right) = {x^2} + \frac{1}{{{x^2}}} + 16\\f(17) = ?\end{array}$

Using the substitution $x + \frac{1}{x} + 4 = t$, we have

$\begin{array}{l}x + \frac{1}{x} = t – 4\\ \Rightarrow {x^2} + \frac{1}{{{x^2}}} + 2 = {(t – 4)^2}\\ \Rightarrow {x^2} + \frac{1}{{{x^2}}} + 16 = {(t – 4)^2} + 14\end{array}$

Now, $f(t) = {(t – 4)^2} + 14$

$\therefore f(17) = {(17 – 4)^2} + 14 = 169 + 14 = 183$

Let $I = \int\limits_0^{\pi /2} {\frac{{dx}}{{1 + {{\tan }^{\sqrt {\tan \alpha } }}x}}}$

$\frac{{dI}}{{d\alpha }} = ?$

We have, $I = \int\limits_0^{\pi /2} {\frac{{dx}}{{1 + {{\tan }^{\sqrt {\tan \alpha } }}(\pi /2 – x)}}} $

$ \Rightarrow I = \int\limits_0^{\pi /2} {\frac{{dx}}{{1 + {{\cot }^{\sqrt {\tan \alpha } }}x}}} = \int\limits_0^{\pi /2} {\frac{{{{\sin }^{\sqrt {\tan \alpha } }}x.dx}}{{{{\sin }^{\sqrt {\tan \alpha } }}x + {{\cos }^{\sqrt {\tan \alpha } }}x}}} $ ……..(A)

Also, $I = \int\limits_0^{\pi /2} {\frac{{dx}}{{1 + {{\tan }^{\sqrt {\tan \alpha } }}x}} = } \int\limits_0^{\pi /2} {\frac{{{{\cos }^{\sqrt {\tan \alpha } }}x.dx}}{{{{\cos }^{\sqrt {\tan \alpha } }}x + {{\sin }^{\sqrt {\tan \alpha } }}x}}}$ ……..(B)

(A) + (B) gives, $2I = \int\limits_0^{\pi /2} {dx} = \frac{\pi }{2}$

$ \Rightarrow I = \frac{\pi }{4}$

$\therefore \frac{{dI}}{{d\alpha }} = 0$

$y = \frac{{{x^2} – \alpha \beta }}{{2x – \alpha – \beta }}$

$x \in \mathbb{R} – \left\{ {\frac{{\alpha + \beta }}{2}} \right\}$

Assuming $\beta > \alpha $ which of the following option(s) is/are correct?

(A) $y \le \alpha $
(B) $y \ge \beta $
(C) $\alpha \le y \le \beta $
(D) $y \in \mathbb{R}$ Continue reading $y = \frac{{{x^2} – \alpha \beta }}{{2x – \alpha – \beta }}$

$x \in \mathbb{R} – \left\{ {\frac{{\alpha + \beta }}{2}} \right\}$