Derivada de $$$\operatorname{asin}{\left(\frac{2 x}{x^{2} + 1} \right)}$$$

La función $$$\operatorname{asin}{\left(\frac{2 x}{x^{2} + 1} \right)}$$$ es la composición $$$f{\left(g{\left(x \right)} \right)}$$$ de dos funciones $$$f{\left(u \right)} = \operatorname{asin}{\left(u \right)}$$$ y $$$g{\left(x \right)} = \frac{2 x}{x^{2} + 1}$$$.

Aplica la regla de la cadena $$$\frac{d}{dx} \left(f{\left(g{\left(x \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dx} \left(g{\left(x \right)}\right)$$$:

$${\color{red}\left(\frac{d}{dx} \left(\operatorname{asin}{\left(\frac{2 x}{x^{2} + 1} \right)}\right)\right)} = {\color{red}\left(\frac{d}{du} \left(\operatorname{asin}{\left(u \right)}\right) \frac{d}{dx} \left(\frac{2 x}{x^{2} + 1}\right)\right)}$$

La derivada del arcoseno es $$$\frac{d}{du} \left(\operatorname{asin}{\left(u \right)}\right) = \frac{1}{\sqrt{1 - u^{2}}}$$$:

$${\color{red}\left(\frac{d}{du} \left(\operatorname{asin}{\left(u \right)}\right)\right)} \frac{d}{dx} \left(\frac{2 x}{x^{2} + 1}\right) = {\color{red}\left(\frac{1}{\sqrt{1 - u^{2}}}\right)} \frac{d}{dx} \left(\frac{2 x}{x^{2} + 1}\right)$$

Volver a la variable original:

$$\frac{\frac{d}{dx} \left(\frac{2 x}{x^{2} + 1}\right)}{\sqrt{1 - {\color{red}\left(u\right)}^{2}}} = \frac{\frac{d}{dx} \left(\frac{2 x}{x^{2} + 1}\right)}{\sqrt{1 - {\color{red}\left(\frac{2 x}{x^{2} + 1}\right)}^{2}}}$$

Aplica la regla del factor constante $$$\frac{d}{dx} \left(c f{\left(x \right)}\right) = c \frac{d}{dx} \left(f{\left(x \right)}\right)$$$ con $$$c = 2$$$ y $$$f{\left(x \right)} = \frac{x}{x^{2} + 1}$$$:

$$\frac{{\color{red}\left(\frac{d}{dx} \left(\frac{2 x}{x^{2} + 1}\right)\right)}}{\sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = \frac{{\color{red}\left(2 \frac{d}{dx} \left(\frac{x}{x^{2} + 1}\right)\right)}}{\sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}}$$

Aplica la regla del cociente $$$\frac{d}{dx} \left(\frac{f{\left(x \right)}}{g{\left(x \right)}}\right) = \frac{\frac{d}{dx} \left(f{\left(x \right)}\right) g{\left(x \right)} - f{\left(x \right)} \frac{d}{dx} \left(g{\left(x \right)}\right)}{g^{2}{\left(x \right)}}$$$ con $$$f{\left(x \right)} = x$$$ y $$$g{\left(x \right)} = x^{2} + 1$$$:

$$\frac{2 {\color{red}\left(\frac{d}{dx} \left(\frac{x}{x^{2} + 1}\right)\right)}}{\sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = \frac{2 {\color{red}\left(\frac{\frac{d}{dx} \left(x\right) \left(x^{2} + 1\right) - x \frac{d}{dx} \left(x^{2} + 1\right)}{\left(x^{2} + 1\right)^{2}}\right)}}{\sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}}$$

La derivada de una suma/diferencia es la suma/diferencia de las derivadas:

$$\frac{2 \left(- x {\color{red}\left(\frac{d}{dx} \left(x^{2} + 1\right)\right)} + \left(x^{2} + 1\right) \frac{d}{dx} \left(x\right)\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = \frac{2 \left(- x {\color{red}\left(\frac{d}{dx} \left(x^{2}\right) + \frac{d}{dx} \left(1\right)\right)} + \left(x^{2} + 1\right) \frac{d}{dx} \left(x\right)\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}}$$

La derivada de una constante es $$$0$$$:

$$\frac{2 \left(- x \left({\color{red}\left(\frac{d}{dx} \left(1\right)\right)} + \frac{d}{dx} \left(x^{2}\right)\right) + \left(x^{2} + 1\right) \frac{d}{dx} \left(x\right)\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = \frac{2 \left(- x \left({\color{red}\left(0\right)} + \frac{d}{dx} \left(x^{2}\right)\right) + \left(x^{2} + 1\right) \frac{d}{dx} \left(x\right)\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}}$$

Aplica la regla de la potencia $$$\frac{d}{dx} \left(x^{n}\right) = n x^{n - 1}$$$ con $$$n = 2$$$:

$$\frac{2 \left(- x {\color{red}\left(\frac{d}{dx} \left(x^{2}\right)\right)} + \left(x^{2} + 1\right) \frac{d}{dx} \left(x\right)\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = \frac{2 \left(- x {\color{red}\left(2 x\right)} + \left(x^{2} + 1\right) \frac{d}{dx} \left(x\right)\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}}$$

Aplica la regla de la potencia $$$\frac{d}{dx} \left(x^{n}\right) = n x^{n - 1}$$$ con $$$n = 1$$$, en otras palabras, $$$\frac{d}{dx} \left(x\right) = 1$$$:

$$\frac{2 \left(- 2 x^{2} + \left(x^{2} + 1\right) {\color{red}\left(\frac{d}{dx} \left(x\right)\right)}\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = \frac{2 \left(- 2 x^{2} + \left(x^{2} + 1\right) {\color{red}\left(1\right)}\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}}$$

Simplificar:

$$\frac{2 \left(1 - x^{2}\right)}{\left(x^{2} + 1\right)^{2} \sqrt{- \frac{4 x^{2}}{\left(x^{2} + 1\right)^{2}} + 1}} = - \frac{2 \left(x - 1\right) \left(x + 1\right)}{\left(x^{2} + 1\right) \left|{x - 1}\right| \left|{x + 1}\right|}$$

Por lo tanto, $$$\frac{d}{dx} \left(\operatorname{asin}{\left(\frac{2 x}{x^{2} + 1} \right)}\right) = - \frac{2 \left(x - 1\right) \left(x + 1\right)}{\left(x^{2} + 1\right) \left|{x - 1}\right| \left|{x + 1}\right|}.$$$