3 Mathematica で方程式を解く - ようこそ

1 3 Mathematica Solve Solve >> ?Solve Solve ( x f(x)=0 . Solve[f[x]==0,x] = Mathematica == {{x->sol}} {{x->sol1},{x->sol2}, ..} F[x] /.{x->a} (F[x]/.x->a ) F[x]/.{{x->a},{x->b},..} F[x] {x->a} {x->a} {x->b} ..) x a F[a] {F[a],F[b],.. } /. ReplaceAll -> ReplaceAll >> ReplaceAll 1 Mathematica x2 3x 4=0 1) Solve[x^2-3*x-4==0,x]2) x/.

2 Solve[x^2-3*x-4==0,x]3) sol:=Solve[x^2-3*x-4==0,x];x/.sol4) x^2-3*x-4/.sol1 1) , {{x->-1},{x->4}} ,x= 1 {x->-1} 2) x/. {{x->-1},{x->4}} x 1 4 {-1,4} 3) {{x->-1},{x->4}} sol sol x x sol 2) ; 4) x2 3x 4 x sol({x->-1},{x->4}) {0,0} Replace ( ) L1=0,L2=0,..,Lm=0 Lk=a1kx+a2ky+ +aknz(k=1,..,m) x,y,..,z . Solve[{L1==0,L2==0.]}

3 , Lm==0},{x,y,..,z}] Solve {} Mathe-matica , Mathematica 2(1) 2x+y=2x y=1 x,y Solve[{2*x+y==2,x-y==1},{x,y}] out[1] ={{x->1, y->0}} .2{x,y}/.Solve[{2*x+y-2==0,x-y-1==0},{x, y}] out[2] ={{1,0}} x y x y 1 0 Mathematica (2) x 2y+3z=22x 3y+4z=33x 8y+13z=8 x,y,z Solve[{x-2*y+3*z==2,2*x-3*y+4*z==3,3*x-8 *y+13*z==8},{x,y,z}] Solve::svars: Solve.

4 >>out[3]={{x->z, y->-1+2z}} z . sol2:=Solve[{x-2*y+3*z==2,2*x-3*y+4*z==3 ,3*x-8*y+13*z==8},{x,y,z}];sol2/.z->c Solve::svars: Solve .>>out[4]={{x->c, y->-1+2c}} , (3) x y=2x y=1 Solve[{x-y==2,x-y==1},{x,y}]3 out[5]{} {} NSolve FindRoot?NSolve ?FindRoot 5 NSolve[f[x]==0,x] f(x)=0 x=a FindRoot[f[x]==0,{x,a}] 3log(x+2) logx=3 Plot [ ,1] (x>0 ) Plot[Log[x+2]-Log[x]-3,{x, ,1},PlotRange->{-1,1}]( logx Log[x] )

5 X x= (x= FindRoot[Log[x+2]-Log[x]==3,{x, }] out[5]{x -> } NSolve NSolve[Log[x+2]-Log[x]==3,x]4 (1)3x 6x 1= x+2 ( ).(2) x 1=x 3 ( x 1 Sqrt[x-1] Sqrt[ ] )(3) 5 x5+2x4+3x3 2x2+5x 5=0 (4)ex2=3sinx ( ).(5)x10=2x x (limx x10/2x=0 ).5)