Maximum and minimum values of $|\sin x|+|\cos x|$

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How to find the maximum and minimum value of $|\sin x|+|\cos x|$? I am not getting any method to solve this problem. I actually have searched lots of sites but they just gave the answer and not the procedure. I want the full and easy way to solve this.

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Let $f(x) = |\sin(x)| + |\cos(x)|$. Then $$f(x + \pi/2) = |\sin(x + \pi/2)| + |\cos(x + \pi/2)| = |\cos(x)| + |-\sin(x)| = f(x),$$ i.e. $f$ is $\pi/2$-periodic. This means that the maximum resp. Minimum of $f$ on the real line is the same as the maximum resp. minimum of $f$ on $[0, \pi/2]$.

On the interval $[0, \pi/2]$ both $\sin$ and $\cos$ are nonnegative, so the equation $f(x) = \sin(x) + \cos(x)$ holds. Now you can apply the standard procedures to determine the maximum resp. minimum of a differentiable function on a compact interval. The maximum is $\sqrt{2}$ for $x = \pi/4$ and the Minimum is $1$ for $x = 0$ or $x = \pi/2$.