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 derivative8((tan2(2x)+1)tan(tan(2x))+tan(2x))(tan2(2x)+1)(tan2(tan(2x))+1)=0Solve this equationThe roots of this equation
x1=−97.3893722612836x2=−43.9822971502571x3=−29.845130209103x4=56.5486677646163x5=62.2158522491989x6=28.2743338823081x7=29.845130209103x8=−81.6814089933346x9=−15.707963267949x10=72.2566310325652x11=95.8185759344887x12=45.553093477052x13=−55.9326669420193x14=−53.4070751110265x15=18.2335550989418x16=−11.9503697917622x17=100.530964914873x18=−9.42477796076938x19=81.6814089933346x20=70.6858347057703x21=−21.9911485751286x22=−14.1371669411541x23=32.0319273584949x24=42.4115008234622x25=−72.2566310325652x26=68.2487278775419x27=15.707963267949x28=50.2654824574367x29=−28.2743338823081x30=−91.722187776701x31=84.2070008243274x32=−6.28318530717959x33=−17.2787595947439x34=−80.1106126665397x35=−87.9645943005142x36=76.014224508752x37=48.6946861306418x38=−20.4203522483337x39=0x40=20.4203522483337x41=89.5353906273091x42=98.0053730838806x43=−65.9734457253857x44=−73.8274273593601x45=−39.8859089924694x46=6.28318530717959x47=−67.5442420521806x48=−36.1283155162826x49=94.2477796076938x50=−61.261056745001x51=65.9734457253857x52=36.1283155162826x53=21.9911485751286x54=−33.9415183668907x55=78.5398163397448x56=40.2247036740703x57=−69.7310392015724x58=−47.7398906264439x59=4.71238898038469x60=−3.75759347618678x61=−89.5353906273091x62=7.85398163397448x63=14.1371669411541x64=26.0875367329163x65=86.3937979737193x66=87.9645943005142x67=12.5663706143592x68=−25.7487420513153x69=51.8362787842316x70=−37.6991118430775x71=−51.8362787842316x72=−1.5707963267949x73=59.6902604182061x74=−83.8682061427265x75=−23.5619449019235x76=−99.9149640922764x77=64.4026493985908x78=43.9822971502571x79=−50.2654824574367x80=37.6991118430775x81=−95.8185759344887x82=−64.4026493985908x83=80.1106126665397x84=73.8274273593601x85=−59.6902604182061x86=−7.85398163397448x87=−75.398223686155x88=−86.3937979737193x89=23.5619449019235x90=92.6769832808989x91=9.42477796076938x92=54.0230759336235x93=−45.553093477052x94=1.5707963267949x95=−58.1194640914112x96=58.1194640914112x97=−94.2477796076938x98=−77.9238155171478x99=−42.4115008234622x100=34.5575191894877x101=−31.4159265358979Сonvexity 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
[100.530964914873,∞)Convex at the intervals
(−∞,−99.9149640922764]