Arc Length in Space
Some Approximations
> | with(plots): |
Warning, the name changecoords has been redefined
> | Int(sqrt(1+4*t^2+(3*t^2-6*t+2)^2),t=0..2); |
> | ArcLength:=evalf(%); |
> | Curve:=spacecurve([t,t^2,t^3-3*t^2+2*t,t=0..2],thickness=3,labels=[x,y,z],axes=boxed,color=red,orientation=[325,75]): |
> | segments:=Array(1..4): |
> | for i from 1 to 4 do segments[i]:=spacecurve([(i-1)*(2/4)+(2/4)*t,((i-1)*(2/4))^2+(2*i-1)*((2/4)^2)*t,((i-1)*(2/4))^3-3*((i-1)*(2/4))^2+2*(i-1)*(2/4)+((i*2/4)^3-3*(i*2/4)^2+2*i*2/4-(((i-1)*(2/4))^3-3*((i-1)*(2/4))^2+2*(i-1)*(2/4)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..4)); |
> | i:='i'; |
> | sum(sqrt((2/4)^2+((2*i-1)*((2/4)^2))^2+(((i*2/4)^3-3*(i*2/4)^2+2*i*2/4-(((i-1)*(2/4))^3-3*((i-1)*(2/4))^2+2*(i-1)*(2/4))))^2),i=1..4); |
> | evalf(%); |
> | ArcLength; |
> | segments:=Array(1..8): |
> | for i from 1 to 8 do segments[i]:=spacecurve([(i-1)*(2/8)+(2/8)*t,((i-1)*(2/8))^2+(2*i-1)*((2/8)^2)*t,((i-1)*(2/8))^3-3*((i-1)*(2/8))^2+2*(i-1)*(2/8)+((i*2/8)^3-3*(i*2/8)^2+2*i*2/8-(((i-1)*(2/8))^3-3*((i-1)*(2/8))^2+2*(i-1)*(2/8)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..8)); |
> | i:='i'; |
> | sum(sqrt((2/8)^2+((2*i-1)*((2/8)^2))^2+(((i*2/8)^3-3*(i*2/8)^2+2*i*2/8-(((i-1)*(2/8))^3-3*((i-1)*(2/8))^2+2*(i-1)*(2/8))))^2),i=1..8); |
> | evalf(%); |
> | ArcLength; |
> | segments:=Array(1..12): |
> | for i from 1 to 12 do segments[i]:=spacecurve([(i-1)*(2/12)+(2/12)*t,((i-1)*(2/12))^2+(2*i-1)*((2/12)^2)*t,((i-1)*(2/12))^3-3*((i-1)*(2/12))^2+2*(i-1)*(2/12)+((i*2/12)^3-3*(i*2/12)^2+2*i*2/12-(((i-1)*(2/12))^3-3*((i-1)*(2/12))^2+2*(i-1)*(2/12)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..12)); |
> | i:='i': |
> | sum(sqrt((2/12)^2+((2*i-1)*((2/12)^2))^2+(((i*2/12)^3-3*(i*2/12)^2+2*i*2/12-(((i-1)*(2/12))^3-3*((i-1)*(2/12))^2+2*(i-1)*(2/12))))^2),i=1..12); |
> | evalf(%); |
> | ArcLength; |
> | segments:=Array(1..16): |
> | for i from 1 to 16 do segments[i]:=spacecurve([(i-1)*(2/16)+(2/16)*t,((i-1)*(2/16))^2+(2*i-1)*((2/16)^2)*t,((i-1)*(2/16))^3-3*((i-1)*(2/16))^2+2*(i-1)*(2/16)+((i*2/16)^3-3*(i*2/16)^2+2*i*2/16-(((i-1)*(2/16))^3-3*((i-1)*(2/16))^2+2*(i-1)*(2/16)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..16)); |
> | i:='i': |
> | sum(sqrt((2/16)^2+((2*i-1)*((2/16)^2))^2+(((i*2/16)^3-3*(i*2/16)^2+2*i*2/16-(((i-1)*(2/16))^3-3*((i-1)*(2/16))^2+2*(i-1)*(2/16))))^2),i=1..16); |
> | evalf(%); |
> | ArcLength; |
> | segments:=Array(1..20): |
> | for i from 1 to 20 do segments[i]:=spacecurve([(i-1)*(2/20)+(2/20)*t,((i-1)*(2/20))^2+(2*i-1)*((2/20)^2)*t,((i-1)*(2/20))^3-3*((i-1)*(2/20))^2+2*(i-1)*(2/20)+((i*2/20)^3-3*(i*2/20)^2+2*i*2/20-(((i-1)*(2/20))^3-3*((i-1)*(2/20))^2+2*(i-1)*(2/20)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..20)); |
> | i:='i': |
> | sum(sqrt((2/20)^2+((2*i-1)*((2/20)^2))^2+(((i*2/20)^3-3*(i*2/20)^2+2*i*2/20-(((i-1)*(2/20))^3-3*((i-1)*(2/20))^2+2*(i-1)*(2/20))))^2),i=1..20); |
> | evalf(%); |
> | ArcLength; |
> | segments:=Array(1..24): |
> | for i from 1 to 24 do segments[i]:=spacecurve([(i-1)*(2/24)+(2/24)*t,((i-1)*(2/24))^2+(2*i-1)*((2/24)^2)*t,((i-1)*(2/24))^3-3*((i-1)*(2/24))^2+2*(i-1)*(2/24)+((i*2/24)^3-3*(i*2/24)^2+2*i*2/24-(((i-1)*(2/24))^3-3*((i-1)*(2/24))^2+2*(i-1)*(2/24)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..24)); |
> | i:='i': |
> | evalf(sum(sqrt((2/24)^2+((2*i-1)*((2/24)^2))^2+(((i*2/24)^3-3*(i*2/24)^2+2*i*2/24-(((i-1)*(2/24))^3-3*((i-1)*(2/24))^2+2*(i-1)*(2/24))))^2),i=1..24)); |
> | ArcLength; |
> |
> | segments:=Array(1..28): |
> | for i from 1 to 28 do segments[i]:=spacecurve([(i-1)*(2/28)+(2/28)*t,((i-1)*(2/28))^2+(2*i-1)*((2/28)^2)*t,((i-1)*(2/28))^3-3*((i-1)*(2/28))^2+2*(i-1)*(2/28)+((i*2/28)^3-3*(i*2/28)^2+2*i*2/28-(((i-1)*(2/28))^3-3*((i-1)*(2/28))^2+2*(i-1)*(2/28)))*t,t=0..1],thickness=3,color=blue):end do: |
> | display(Curve,seq(segments[k],k=1..28)); |
> | i:='i': |
> | evalf(sum(sqrt((2/28)^2+((2*i-1)*((2/28)^2))^2+(((i*2/28)^3-3*(i*2/28)^2+2*i*2/28-(((i-1)*(2/28))^3-3*((i-1)*(2/28))^2+2*(i-1)*(2/28))))^2),i=1..28)); |
> | ArcLength; |
> | evalf(sum(sqrt((2/100)^2+((2*i-1)*((2/100)^2))^2+(((i*2/100)^3-3*(i*2/100)^2+2*i*2/100-(((i-1)*(2/100))^3-3*((i-1)*(2/100))^2+2*(i-1)*(2/100))))^2),i=1..100)); |
> | evalf(sum(sqrt((2/1000)^2+((2*i-1)*((2/1000)^2))^2+(((i*2/1000)^3-3*(i*2/1000)^2+2*i*2/1000-(((i-1)*(2/1000))^3-3*((i-1)*(2/1000))^2+2*(i-1)*(2/1000))))^2),i=1..1000)); |
> | evalf(sum(sqrt((2/10000)^2+((2*i-1)*((2/10000)^2))^2+(((i*2/10000)^3-3*(i*2/10000)^2+2*i*2/10000-(((i-1)*(2/10000))^3-3*((i-1)*(2/10000))^2+2*(i-1)*(2/10000))))^2),i=1..10000)); |
> | evalf(sum(sqrt((2/20000)^2+((2*i-1)*((2/20000)^2))^2+(((i*2/20000)^3-3*(i*2/20000)^2+2*i*2/20000-(((i-1)*(2/20000))^3-3*((i-1)*(2/20000))^2+2*(i-1)*(2/20000))))^2),i=1..20000)); |
> | ArcLength; |
> |