In order to find the extrema, we need to solve the equation
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(the derivative equals zero),
and the roots of this equation are the extrema of this function:
$$\frac{d}{d x} f{\left(x \right)} = $$
the first derivative$$- \sqrt{x} \sin{\left(x \right)} + \frac{\cos{\left(x \right)}}{2 \sqrt{x}} = 0$$
Solve this equationThe roots of this equation
$$x_{1} = -9.4774857054208$$
$$x_{2} = -43.9936619344429$$
$$x_{3} = 62.8398096434599$$
$$x_{4} = 72.26355003974$$
$$x_{5} = -69.1222718113619$$
$$x_{6} = 47.1344973476771$$
$$x_{7} = -53.4164352526291$$
$$x_{8} = 22.013857636623$$
$$x_{9} = -18.8760383379859$$
$$x_{10} = -65.9810235167388$$
$$x_{11} = 37.7123693157661$$
$$x_{12} = 9.4774857054208$$
$$x_{13} = -75.4048544617952$$
$$x_{14} = -97.3945059759883$$
$$x_{15} = -40.8529429059734$$
$$x_{16} = 3.29231002128209$$
$$x_{17} = -50.2754273458806$$
$$x_{18} = 15.7397193560049$$
$$x_{19} = -6.36162039206566$$
$$x_{20} = -37.7123693157661$$
$$x_{21} = 0.653271187094403$$
$$x_{22} = 81.6875298021918$$
$$x_{23} = 50.2754273458806$$
$$x_{24} = -31.43183263459$$
$$x_{25} = 56.5575080935408$$
$$x_{26} = -94.253084424113$$
$$x_{27} = 97.3945059759883$$
$$x_{28} = 53.4164352526291$$
$$x_{29} = -78.5461819355535$$
$$x_{30} = -84.8288957966139$$
$$x_{31} = -22.013857636623$$
$$x_{32} = -59.6986356231676$$
$$x_{33} = -12.6060134442754$$
$$x_{34} = 12.6060134442754$$
$$x_{35} = -87.970277977177$$
$$x_{36} = 87.970277977177$$
$$x_{37} = 25.1526172579356$$
$$x_{38} = -28.2920048800691$$
$$x_{39} = 18.8760383379859$$
$$x_{40} = 6.36162039206566$$
$$x_{41} = 75.4048544617952$$
$$x_{42} = 65.9810235167388$$
$$x_{43} = -15.7397193560049$$
$$x_{44} = -56.5575080935408$$
$$x_{45} = -62.8398096434599$$
$$x_{46} = 43.9936619344429$$
$$x_{47} = 94.253084424113$$
$$x_{48} = 84.8288957966139$$
$$x_{49} = 78.5461819355535$$
$$x_{50} = 40.8529429059734$$
$$x_{51} = -91.1116746699497$$
$$x_{52} = -47.1344973476771$$
$$x_{53} = -34.5719807601687$$
$$x_{54} = -100.535938219808$$
$$x_{55} = 91.1116746699497$$
$$x_{56} = -3.29231002128209$$
$$x_{57} = 31.43183263459$$
$$x_{58} = 34.5719807601687$$
$$x_{59} = -81.6875298021918$$
$$x_{60} = -25.1526172579356$$
$$x_{61} = -72.26355003974$$
$$x_{62} = 69.1222718113619$$
$$x_{63} = 59.6986356231676$$
$$x_{64} = 28.2920048800691$$
$$x_{65} = 100.535938219808$$
The values of the extrema at the points:
(-9.477485705420795, -3.07427725087097*I)
(-43.993661934442905, 6.63234347961736*I)
(62.839809643459915, 7.92690554538958)
(72.26355003974, -8.50059354672143)
(-69.1222718113619, 8.3137630000695*I)
(47.13449734767706, -6.86507057309731)
(-53.41643525262913, -7.3083346567585*I)
(22.013857636622962, -4.69068300028599)
(-18.876038337985854, 4.34313289225214*I)
(-65.9810235167388, -8.12263718050406*I)
(37.712369315766125, 6.14050009006662)
(9.477485705420795, -3.07427725087097)
(-75.40485446179518, 8.68340596604541*I)
(-97.39450597598831, -9.86873543893722*I)
(-40.85294290597337, -6.39115203326596*I)
(3.2923100212820864, -1.79390283516354)
(-50.27542734588058, 7.0901660932241*I)
(15.73971935600487, -3.96533125786786)
(-6.361620392065665, 2.51447081861791*I)
(-37.712369315766125, 6.14050009006662*I)
(0.6532711870944031, 0.641832750676974)
(81.6875298021918, 9.03794608714833)
(50.27542734588058, 7.0901660932241)
(-31.431832634590037, 5.60570075250289*I)
(56.55750809354077, 7.52017873187663)
(-94.25308442411298, 9.70826617196213*I)
(97.39450597598831, -9.86873543893722)
(53.41643525262913, -7.3083346567585)
(-78.54618193555346, -8.86244882770153*I)
(-84.8288957966139, -9.21010036807552*I)
(-22.013857636622962, -4.69068300028599*I)
(-59.698635623167625, -7.72621823510751*I)
(-12.606013444275414, 3.54770528507369*I)
(12.606013444275414, 3.54770528507369)
(-87.970277977177, 9.3790957026809*I)
(87.970277977177, 9.3790957026809)
(25.152617257935617, 5.01424788582548)
(-28.292004880069126, -5.31819247681142*I)
(18.876038337985854, 4.34313289225214)
(6.361620392065665, 2.51447081861791)
(75.40485446179518, 8.68340596604541)
(65.9810235167388, -8.12263718050406)
(-15.73971935600487, -3.96533125786786*I)
(-56.55750809354077, 7.52017873187663*I)
(-62.839809643459915, 7.92690554538958*I)
(43.993661934442905, 6.63234347961736)
(94.25308442411298, 9.70826617196213)
(84.8288957966139, -9.21010036807552)
(78.54618193555346, -8.86244882770153)
(40.85294290597337, -6.39115203326596)
(-91.11167466994975, -9.54509983536653*I)
(-47.13449734767706, -6.86507057309731*I)
(-34.57198076016866, -5.87917944809784*I)
(-100.53593821980844, 10.0266371036526*I)
(91.11167466994975, -9.54509983536653)
(-3.2923100212820864, -1.79390283516354*I)
(31.431832634590037, 5.60570075250289)
(34.57198076016866, -5.87917944809784)
(-81.6875298021918, 9.03794608714833*I)
(-25.152617257935617, 5.01424788582548*I)
(-72.26355003974, -8.50059354672143*I)
(69.1222718113619, 8.3137630000695)
(59.698635623167625, -7.72621823510751)
(28.292004880069126, -5.31819247681142)
(100.53593821980844, 10.0266371036526)
Intervals of increase and decrease of the function:Let's find intervals where the function increases and decreases, as well as minima and maxima of the function, for this let's look how the function behaves itself in the extremas and at the slightest deviation from:
Minima of the function at points:
$$x_{1} = 72.26355003974$$
$$x_{2} = 47.1344973476771$$
$$x_{3} = 22.013857636623$$
$$x_{4} = 9.4774857054208$$
$$x_{5} = 3.29231002128209$$
$$x_{6} = 15.7397193560049$$
$$x_{7} = 97.3945059759883$$
$$x_{8} = 53.4164352526291$$
$$x_{9} = 65.9810235167388$$
$$x_{10} = 84.8288957966139$$
$$x_{11} = 78.5461819355535$$
$$x_{12} = 40.8529429059734$$
$$x_{13} = 91.1116746699497$$
$$x_{14} = 34.5719807601687$$
$$x_{15} = 59.6986356231676$$
$$x_{16} = 28.2920048800691$$
Maxima of the function at points:
$$x_{16} = 62.8398096434599$$
$$x_{16} = 37.7123693157661$$
$$x_{16} = 0.653271187094403$$
$$x_{16} = 81.6875298021918$$
$$x_{16} = 50.2754273458806$$
$$x_{16} = 56.5575080935408$$
$$x_{16} = 12.6060134442754$$
$$x_{16} = 87.970277977177$$
$$x_{16} = 25.1526172579356$$
$$x_{16} = 18.8760383379859$$
$$x_{16} = 6.36162039206566$$
$$x_{16} = 75.4048544617952$$
$$x_{16} = 43.9936619344429$$
$$x_{16} = 94.253084424113$$
$$x_{16} = 31.43183263459$$
$$x_{16} = 69.1222718113619$$
$$x_{16} = 100.535938219808$$
Decreasing at intervals
$$\left[97.3945059759883, \infty\right)$$
Increasing at intervals
$$\left(-\infty, 3.29231002128209\right]$$