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 derivativex2cos(2x)−x2sin(2x)=0Solve this equationThe roots of this equation
x1=84.0346285545694x2=24.3370721159772x3=−63.6133213216672x4=11.7597262493445x5=−62.0424254948814x6=−79.3220628366317x7=−46.3330961388114x8=−54.1878598258373x9=30.6223651301872x10=96.6013861664138x11=−85.6054794697228x12=−93.4597065202651x13=−76.1803402100956x14=−68.3259813506395x15=−3.86262591846885x16=−91.8888644664832x17=−27.4798391439445x18=3.86262591846885x19=−33.7647173885721x20=−13.3330271294063x21=−47.9040693934309x22=66.7550989265392x23=25.9084912436398x24=22.7655670069956x25=32.1935597952787x26=8.61037763596538x27=−60.4715244985757x28=10.1856514796438x29=99.7430603324317x30=−90.3180208221014x31=44.7621104652086x32=88.7471755026564x33=16.4781945199112x34=−10.1856514796438x35=−40.0490643144726x36=−38.4780131551656x37=−69.8968599047927x38=−19.6222161805821x39=54.1878598258373x40=−41.6200962353617x41=62.0424254948814x42=−35.3358428558098x43=51.0459832324538x44=63.6133213216672x45=204.987701063789x46=2.24670472895453x47=74.6094747920599x48=47.9040693934309x49=33.7647173885721x50=46.3330961388114x51=40.0490643144726x52=−98.172223901556x53=98.172223901556x54=41.6200962353617x55=77.7512028363303x56=−58.9006179191122x57=91.8888644664832x58=−49.4750314121659x59=−24.3370721159772x60=−57.3297052975115x61=69.8968599047927x62=−99.7430603324317x63=−82.4637755597094x64=90.3180208221014x65=60.4715244985757x66=−11.7597262493445x67=−71.4677348441946x68=−25.9084912436398x69=68.3259813506395x70=38.4780131551656x71=−55.7587861230655x72=13.3330271294063x73=18.0503111221878x74=−16.4781945199112x75=−2.24670472895453x76=55.7587861230655x77=−84.0346285545694x78=85.6054794697228x79=76.1803402100956x80=52.6169257678188x81=82.4637755597094x82=−5.45206082971445x83=−18.0503111221878x84=−77.7512028363303x85=−32.1935597952787x86=19.6222161805821The values of the extrema at the points:
(84.0346285545694, -0.0118996456204748)
(24.337072115977193, -0.0410809080835075)
(-63.613321321667165, 0.015719492253233)
(11.759726249344503, -0.0849592339552253)
(-62.04242549488138, -0.0161174796093628)
(-79.32206283663172, 0.0126065825610424)
(-46.33309613881142, -0.0215815876990685)
(-54.18785982583734, 0.0184535325015639)
(30.6223651301872, -0.0326515186419956)
(96.60138616641379, -0.0103516796697785)
(-85.60547946972281, 0.0116812959808693)
(-93.45970652026512, -0.0106996450858762)
(-76.18034021009562, 0.0131264635863328)
(-68.3259813506395, -0.0146353291349374)
(-3.8626259184688534, 0.256749107051798)
(-91.88886446648316, 0.0108825503716759)
(-27.479839143944467, -0.0363842926436063)
(3.8626259184688534, 0.256749107051798)
(-33.76471738857206, -0.0296134678930985)
(-13.333027129406338, 0.0749490399878624)
(-47.90406939343085, 0.0208739162691316)
(66.75509892653919, 0.0149797089170242)
(25.908491243639833, 0.0385901989751759)
(22.76556700699564, 0.0439153964569649)
(32.19355979527871, 0.0310583676149227)
(8.610377635965385, -0.115943604692308)
(-60.47152449857575, 0.0165361437007152)
(10.18565147964378, 0.0980592480281483)
(99.74306033243167, -0.0100256341886906)
(-90.31802082210145, -0.01107181786798)
(44.76211046520859, 0.0223389292683471)
(88.7471755026564, 0.0112677854121748)
(16.478194519911238, 0.0606583423726206)
(-10.18565147964378, 0.0980592480281483)
(-40.04906431447256, -0.024967426643558)
(-38.47801315516559, 0.0259866739740854)
(-69.8968599047927, 0.0143064283116353)
(-19.622216180582097, 0.0509461061857615)
(54.18785982583734, 0.0184535325015639)
(-41.6200962353617, 0.0240251209641055)
(62.04242549488138, -0.0161174796093628)
(-35.33584285580975, 0.0282970441297328)
(51.04598323245382, 0.0195892402934823)
(63.613321321667165, 0.015719492253233)
(204.98770106378876, 0.00487832694374757)
(2.246704728954532, -0.434467256422443)
(74.60947479205991, -0.0134028224709878)
(47.90406939343085, 0.0208739162691316)
(33.76471738857206, -0.0296134678930985)
(46.33309613881142, -0.0215815876990685)
(40.04906431447256, -0.024967426643558)
(-98.172223901556, 0.0101860484638785)
(98.172223901556, 0.0101860484638785)
(41.6200962353617, 0.0240251209641055)
(77.75120283633034, -0.0128612714243586)
(-58.90061791911219, -0.0169771388955304)
(91.88886446648316, 0.0108825503716759)
(-49.47503141216594, -0.0202111834730081)
(-24.337072115977193, -0.0410809080835075)
(-57.32970529751154, 0.0174423008954086)
(69.8968599047927, 0.0143064283116353)
(-99.74306033243167, -0.0100256341886906)
(-82.46377555970939, 0.0121263137918205)
(90.31802082210145, -0.01107181786798)
(60.47152449857575, 0.0165361437007152)
(-11.759726249344503, -0.0849592339552253)
(-71.46773484419464, -0.0139919857530453)
(-25.908491243639833, 0.0385901989751759)
(68.3259813506395, -0.0146353291349374)
(38.47801315516559, 0.0259866739740854)
(-55.758786123065505, -0.0179336722809866)
(13.333027129406338, 0.0749490399878624)
(18.050311122187804, -0.0553794646022984)
(-16.478194519911238, 0.0606583423726206)
(-2.246704728954532, -0.434467256422443)
(55.758786123065505, -0.0179336722809866)
(-84.0346285545694, -0.0118996456204748)
(85.60547946972281, 0.0116812959808693)
(76.18034021009562, 0.0131264635863328)
(52.6169257678188, -0.0190044332375671)
(82.46377555970939, 0.0121263137918205)
(-5.4520608297144495, -0.182650405646115)
(-18.050311122187804, -0.0553794646022984)
(-77.75120283633034, -0.0128612714243586)
(-32.19355979527871, 0.0310583676149227)
(19.622216180582097, 0.0509461061857615)
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=84.0346285545694x2=24.3370721159772x3=11.7597262493445x4=−62.0424254948814x5=−46.3330961388114x6=30.6223651301872x7=96.6013861664138x8=−93.4597065202651x9=−68.3259813506395x10=−27.4798391439445x11=−33.7647173885721x12=8.61037763596538x13=99.7430603324317x14=−90.3180208221014x15=−40.0490643144726x16=62.0424254948814x17=2.24670472895453x18=74.6094747920599x19=33.7647173885721x20=46.3330961388114x21=40.0490643144726x22=77.7512028363303x23=−58.9006179191122x24=−49.4750314121659x25=−24.3370721159772x26=−99.7430603324317x27=90.3180208221014x28=−11.7597262493445x29=−71.4677348441946x30=68.3259813506395x31=−55.7587861230655x32=18.0503111221878x33=−2.24670472895453x34=55.7587861230655x35=−84.0346285545694x36=52.6169257678188x37=−5.45206082971445x38=−18.0503111221878x39=−77.7512028363303Maxima of the function at points:
x39=−63.6133213216672x39=−79.3220628366317x39=−54.1878598258373x39=−85.6054794697228x39=−76.1803402100956x39=−3.86262591846885x39=−91.8888644664832x39=3.86262591846885x39=−13.3330271294063x39=−47.9040693934309x39=66.7550989265392x39=25.9084912436398x39=22.7655670069956x39=32.1935597952787x39=−60.4715244985757x39=10.1856514796438x39=44.7621104652086x39=88.7471755026564x39=16.4781945199112x39=−10.1856514796438x39=−38.4780131551656x39=−69.8968599047927x39=−19.6222161805821x39=54.1878598258373x39=−41.6200962353617x39=−35.3358428558098x39=51.0459832324538x39=63.6133213216672x39=204.987701063789x39=47.9040693934309x39=−98.172223901556x39=98.172223901556x39=41.6200962353617x39=91.8888644664832x39=−57.3297052975115x39=69.8968599047927x39=−82.4637755597094x39=60.4715244985757x39=−25.9084912436398x39=38.4780131551656x39=13.3330271294063x39=−16.4781945199112x39=85.6054794697228x39=76.1803402100956x39=82.4637755597094x39=−32.1935597952787x39=19.6222161805821Decreasing at intervals
[99.7430603324317,∞)Increasing at intervals
(−∞,−99.7430603324317]