The points of intersection with the X-axis coordinate
Graph of the function intersects the axis X at f = 0 so we need to solve the equation: xcos(x)=0 Solve this equation The points of intersection with the axis X:
The points of intersection with the Y axis coordinate
The graph crosses Y axis when x equals 0: substitute x = 0 to sqrt(x)*cos(x). 0cos(0) The result: f(0)=0 The point:
(0, 0)
Extrema of the function
In order to find the extrema, we need to solve the equation dxdf(x)=0 (the derivative equals zero), and the roots of this equation are the extrema of this function: dxdf(x)= the first derivative −xsin(x)+2xcos(x)=0 Solve this equation The roots of this equation x1=−9.4774857054208 x2=−43.9936619344429 x3=62.8398096434599 x4=72.26355003974 x5=−69.1222718113619 x6=47.1344973476771 x7=−53.4164352526291 x8=22.013857636623 x9=−18.8760383379859 x10=−65.9810235167388 x11=37.7123693157661 x12=9.4774857054208 x13=−75.4048544617952 x14=−97.3945059759883 x15=−40.8529429059734 x16=3.29231002128209 x17=−50.2754273458806 x18=15.7397193560049 x19=−6.36162039206566 x20=−37.7123693157661 x21=0.653271187094403 x22=81.6875298021918 x23=50.2754273458806 x24=−31.43183263459 x25=56.5575080935408 x26=−94.253084424113 x27=97.3945059759883 x28=53.4164352526291 x29=−78.5461819355535 x30=−84.8288957966139 x31=−22.013857636623 x32=−59.6986356231676 x33=−12.6060134442754 x34=12.6060134442754 x35=−87.970277977177 x36=87.970277977177 x37=25.1526172579356 x38=−28.2920048800691 x39=18.8760383379859 x40=6.36162039206566 x41=75.4048544617952 x42=65.9810235167388 x43=−15.7397193560049 x44=−56.5575080935408 x45=−62.8398096434599 x46=43.9936619344429 x47=94.253084424113 x48=84.8288957966139 x49=78.5461819355535 x50=40.8529429059734 x51=−91.1116746699497 x52=−47.1344973476771 x53=−34.5719807601687 x54=−100.535938219808 x55=91.1116746699497 x56=−3.29231002128209 x57=31.43183263459 x58=34.5719807601687 x59=−81.6875298021918 x60=−25.1526172579356 x61=−72.26355003974 x62=69.1222718113619 x63=59.6986356231676 x64=28.2920048800691 x65=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: x1=72.26355003974 x2=47.1344973476771 x3=22.013857636623 x4=9.4774857054208 x5=3.29231002128209 x6=15.7397193560049 x7=97.3945059759883 x8=53.4164352526291 x9=65.9810235167388 x10=84.8288957966139 x11=78.5461819355535 x12=40.8529429059734 x13=91.1116746699497 x14=34.5719807601687 x15=59.6986356231676 x16=28.2920048800691 Maxima of the function at points: x16=62.8398096434599 x16=37.7123693157661 x16=0.653271187094403 x16=81.6875298021918 x16=50.2754273458806 x16=56.5575080935408 x16=12.6060134442754 x16=87.970277977177 x16=25.1526172579356 x16=18.8760383379859 x16=6.36162039206566 x16=75.4048544617952 x16=43.9936619344429 x16=94.253084424113 x16=31.43183263459 x16=69.1222718113619 x16=100.535938219808 Decreasing at intervals [97.3945059759883,∞) Increasing at intervals (−∞,3.29231002128209]
Inflection points
Let's find the inflection points, we'll need to solve the equation for this dx2d2f(x)=0 (the second derivative equals zero), the roots of this equation will be the inflection points for the specified function graph: dx2d2f(x)= the second derivative −(xcos(x)+xsin(x)+4x23cos(x))=0 Solve this equation The roots of this equation x1=−36.1559611393004 x2=26.7409029817025 x3=80.1230923289863 x4=86.4053704242642 x5=42.4350586138523 x6=−76.9820087826371 x7=−7.97819025123437 x8=−70.6999773315004 x9=−33.0169941017832 x10=67.559042028453 x11=−67.559042028453 x12=−11.0853581860961 x13=51.8555589377593 x14=58.136661973445 x15=33.0169941017832 x16=−48.7152085571549 x17=−26.7409029817025 x18=7.97819025123437 x19=−14.2073505099925 x20=−73.8409685283396 x21=−23.6042658400483 x22=4.91125081295869 x23=89.5465571901753 x24=36.1559611393004 x25=64.4181707871237 x26=−54.9960510556604 x27=76.9820087826371 x28=2.0090972384408 x29=17.3363302997334 x30=−89.5465571901753 x31=11.0853581860961 x32=−124.100967466518 x33=−80.1230923289863 x34=−45.5750291575042 x35=−64.4181707871237 x36=54.9960510556604 x37=−92.6877714581404 x38=92.6877714581404 x39=29.8785771570692 x40=20.4691384083001 x41=14.2073505099925 x42=83.2642142711524 x43=−58.136661973445 x44=70.6999773315004 x45=−51.8555589377593 x46=−83.2642142711524 x47=−95.8290105250036 x48=−42.4350586138523 x49=39.2953468672842 x50=23.6042658400483 x51=−133.525176756856 x52=45.5750291575042 x53=−61.2773734476957 x54=95.8290105250036 x55=−39.2953468672842 x56=−86.4053704242642 x57=−2.0090972384408 x58=−98.9702720305701 x59=−4.91125081295869 x60=−20.4691384083001 x61=61.2773734476957 x62=98.9702720305701 x63=−29.8785771570692 x64=−17.3363302997334 x65=73.8409685283396 x66=48.7152085571549
Сonvexity and concavity intervals: Let’s find the intervals where the function is convex or concave, for this look at the behaviour of the function at the inflection points: Concave at the intervals [95.8290105250036,∞) Convex at the intervals (−∞,2.0090972384408]
Horizontal asymptotes
Let’s find horizontal asymptotes with help of the limits of this function at x->+oo and x->-oo x→−∞lim(xcos(x))=⟨−∞,∞⟩i Let's take the limit so, equation of the horizontal asymptote on the left: y=⟨−∞,∞⟩i x→∞lim(xcos(x))=⟨−∞,∞⟩ Let's take the limit so, equation of the horizontal asymptote on the right: y=⟨−∞,∞⟩
Inclined asymptotes
Inclined asymptote can be found by calculating the limit of sqrt(x)*cos(x), divided by x at x->+oo and x ->-oo x→−∞lim(xcos(x))=0 Let's take the limit so, inclined coincides with the horizontal asymptote on the right x→∞lim(xcos(x))=0 Let's take the limit so, inclined coincides with the horizontal asymptote on the left
Even and odd functions
Let's check, whether the function even or odd by using relations f = f(-x) и f = -f(-x). So, check: xcos(x)=−xcos(x) - No xcos(x)=−−xcos(x) - No so, the function not is neither even, nor odd