Průběh funkce Předpis funkce: Pracujeme s reálnými funkcemi: > with(RealDomain); Warning, these protected names have been redefined and unprotected: Im, Re, `^`, arccos, arccosh, arccot, arccoth, arccsc, arccsch, arcsec, arcsech, arcsin, arcsinh, arctan, arctanh, cos, cosh, cot, coth, csc, csch, eval, exp, expand, limit, ln, log, sec, sech, signum, simplify, sin, sinh, solve, sqrt, surd, tan, tanh [Im, Re, ^, arccos, arccosh, arccot, arccoth, arccsc, arccsch, arcsec, arcsech, arcsin, arcsinh, arctan, arctanh, cos, cosh, cot, coth, csc, csch, eval, exp, expand, limit, ln, log, sec, sech, signum, simplify, sin, sinh, solve, sqrt, surd, tan, tanh] > f := x^3/(x^4+1); 3 x f := ------ 4 x + 1 Definiční obor (nutno pro každou funkci zvlášť) > solve(x^4+1=0,x); Dále limity v bodech nespojitosti > Limit(f, x=a, left)=limit(f, x=a, left); / 3 \ 3 | x | a lim |------| = ------ x -> a- | 4 | 4 \x + 1/ a + 1 > Limit(f, x=a, right)=limit(f, x=a, right); / 3 \ 3 | x | a lim |------| = ------ x -> a+ | 4 | 4 \x + 1/ a + 1 Je funkce sudá (příp. lichá)? > eval(f,x=-x); 3 x - ------ 4 x + 1 Je několik způsobů, jak ukázat, že je: LICHA: f(x) = –f(–x) > evalb(eval(f,x=x)=-eval(f,x=-x)); true > iszero(eval(f,x=x)+eval(f,x=-x)); iszero(0) > type(f,oddfunc(x)); true A SUDA... f(x) = f(–x) > evalb(eval(f,x=x)=eval(f,x=-x)); false > type(f,evenfunc(x)); false První derivace > df := diff(f,x); 2 6 3 x 4 x df := ------ - --------- 4 2 x + 1 / 4 \ \x + 1/ > NuloveBody := solve(df = 0,x); (1/4) (1/4) NuloveBody := 0, 0, 3 , -3 > Rostoucí := solve(df>0,x); > Klesající := solve(df<0,x); / / (1/4)\ \ / / (1/4)\\ Rostouc? := RealRange\Open\-3 /, Open(0)/, RealRange\Open(0), Open\3 // / / (1/4)\\ Klesaj?c? := RealRange\-infinity, Open\-3 //, / / (1/4)\ \ RealRange\Open\3 /, infinity/ Druhá derivace > d2f := diff(df,x); > d2f := diff(f,x$2); 5 9 6 x 36 x 32 x d2f := ------ - --------- + --------- 4 2 3 x + 1 / 4 \ / 4 \ \x + 1/ \x + 1/ 5 9 6 x 36 x 32 x d2f := ------ - --------- + --------- 4 2 3 x + 1 / 4 \ / 4 \ \x + 1/ \x + 1/ Inflexní body > InflexníBod := solve(d2f = 0,x); (1/4) (1/4) / (1/2)\ / (1/2)\ Inflexn?Bod := 0, -\6 + 33 / , \6 + 33 / , (1/4) / (1/2)\ -\6 - 33 / , (1/4) / (1/2)\ \6 - 33 / > with(Student[Calculus1]): > InflectionPoints(f); [ (1/4) (1/4) (1/4) [ / (1/2)\ / (1/2)\ / (1/2)\ [-\6 + 33 / , -\6 - 33 / , 0, \6 - 33 / , (1/4)] / (1/2)\ ] \6 + 33 / ] Extrémy > eval(d2f,x=0); > eval(d2f,x=NuloveBody[3]); > eval(d2f,x=NuloveBody[4]); 0 3 (1/4) - - 3 4 3 (1/4) - 3 4 Konvexnost a konkávnost > Konvexní := solve(d2f>0,x); > Konkávní := solve(d2f<0,x); / / (1/4)\ / (1/4)\\ | | / (1/2)\ | | / (1/2)\ || Konvexn? := RealRange\Open\-\6 + 33 / /, Open\-\6 - 33 / //, / / (1/4)\\ | |/ (1/2)\ || RealRange\Open(0), Open\\6 - 33 / //, / / (1/4)\ \ | |/ (1/2)\ | | RealRange\Open\\6 + 33 / /, infinity/ / / (1/4)\\ | | / (1/2)\ || Konk?vn? := RealRange\-infinity, Open\-\6 + 33 / //, / / (1/4)\ \ | | / (1/2)\ | | RealRange\Open\-\6 - 33 / /, Open(0)/, / / (1/4)\ / (1/4)\\ | |/ (1/2)\ | |/ (1/2)\ || RealRange\Open\\6 - 33 / /, Open\\6 + 33 / // Asymptota se směrnicí > k:=limit(f/x,x=infinity); k := 0 > q:=limit(f-x*k,x=infinity); q := 0 > Asymptota := k*x+q; Asymptota := 0 A nakonec graf: > plot([f,Asymptota],x=-10..10);