Derivative of tan(x/2 + pi/4)

The calculator will find the derivative of

\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}

, with steps shown.

Your Input

Find $\frac{d}{dx} \left(\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}\right)$ .

Solution

The function $\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}$ is the composition $f{\left(g{\left(x \right)} \right)}$ of two functions $f{\left(u \right)} = \tan{\left(u \right)}$ and $g{\left(x \right)} = \frac{x}{2} + \frac{\pi}{4}$ .

Apply the chain rule $\frac{d}{dx} \left(f{\left(g{\left(x \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dx} \left(g{\left(x \right)}\right)$ :

{\color{red}\left(\frac{d}{dx} \left(\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}\right)\right)} = {\color{red}\left(\frac{d}{du} \left(\tan{\left(u \right)}\right) \frac{d}{dx} \left(\frac{x}{2} + \frac{\pi}{4}\right)\right)}

The derivative of the tangent is $\frac{d}{du} \left(\tan{\left(u \right)}\right) = \sec^{2}{\left(u \right)}$ :

{\color{red}\left(\frac{d}{du} \left(\tan{\left(u \right)}\right)\right)} \frac{d}{dx} \left(\frac{x}{2} + \frac{\pi}{4}\right) = {\color{red}\left(\sec^{2}{\left(u \right)}\right)} \frac{d}{dx} \left(\frac{x}{2} + \frac{\pi}{4}\right)

Return to the old variable:

\sec^{2}{\left({\color{red}\left(u\right)} \right)} \frac{d}{dx} \left(\frac{x}{2} + \frac{\pi}{4}\right) = \sec^{2}{\left({\color{red}\left(\frac{x}{2} + \frac{\pi}{4}\right)} \right)} \frac{d}{dx} \left(\frac{x}{2} + \frac{\pi}{4}\right)

The derivative of a sum/difference is the sum/difference of derivatives:

\sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} {\color{red}\left(\frac{d}{dx} \left(\frac{x}{2} + \frac{\pi}{4}\right)\right)} = \sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} {\color{red}\left(\frac{d}{dx} \left(\frac{x}{2}\right) + \frac{d}{dx} \left(\frac{\pi}{4}\right)\right)}

The derivative of a constant is $0$ :

\left({\color{red}\left(\frac{d}{dx} \left(\frac{\pi}{4}\right)\right)} + \frac{d}{dx} \left(\frac{x}{2}\right)\right) \sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} = \left({\color{red}\left(0\right)} + \frac{d}{dx} \left(\frac{x}{2}\right)\right) \sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)}

Apply the constant multiple rule $\frac{d}{dx} \left(c f{\left(x \right)}\right) = c \frac{d}{dx} \left(f{\left(x \right)}\right)$ with $c = \frac{1}{2}$ and $f{\left(x \right)} = x$ :

\sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} {\color{red}\left(\frac{d}{dx} \left(\frac{x}{2}\right)\right)} = \sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} {\color{red}\left(\frac{\frac{d}{dx} \left(x\right)}{2}\right)}

Apply the power rule $\frac{d}{dx} \left(x^{n}\right) = n x^{n - 1}$ with $n = 1$ , in other words, $\frac{d}{dx} \left(x\right) = 1$ :

\frac{\sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} {\color{red}\left(\frac{d}{dx} \left(x\right)\right)}}{2} = \frac{\sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)} {\color{red}\left(1\right)}}{2}

Simplify:

\frac{\sec^{2}{\left(\frac{x}{2} + \frac{\pi}{4} \right)}}{2} = \frac{1}{1 - \sin{\left(x \right)}}

Thus, $\frac{d}{dx} \left(\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}\right) = \frac{1}{1 - \sin{\left(x \right)}}$ .

Answer

$\frac{d}{dx} \left(\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}\right) = \frac{1}{1 - \sin{\left(x \right)}}$ A

Derivative of tan⁡(x2+π4)\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}tan(2x​+4π​)

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Answer

Derivative of $\tan{\left(\frac{x}{2} + \frac{\pi}{4} \right)}$