Hi,
I am using 5.9.3 to solve for the constants of a differential equation.
In doing so, I was dealt a new label which I've not seen before. The
output contains %r1 which could more clearly be represented by its value
(as seen below):
(%i1) display2d:false$
(%i2) v(x):=1/24*wo*x^4+C1/6*wo*x^3+C2/2*wo*x^2+C3*x+C4$
(%i3) z(x):=1/24*wo*x^4+C5/6*wo*x^3+C6/2*wo*x^2+C7*x+C8$
(%i4) dv:diff(v(x),x,1)$
(%i5) ddv:diff(v(x),x,2)$
(%i6) dddv:diff(v(x),x,3)$
(%i7) ddddv:diff(v(x),x,4)$
(%i8) dz:diff(z(x),x,1)$
(%i9) ddz:diff(z(x),x,2)$
(%i10) dddz:diff(z(x),x,3)$
(%i11) ddddz:diff(z(x),x,4)$
(%i12) bc1:v(0)=0$
(%i13) bc2:ev(dv,x=0)=0$
(%i14) bc3:ev(ddz,x=L)=0$
(%i15) bc4:ev(dddz,x=L)=0$
(%i16) bc5:v(L/2)=0$
(%i17) bc6:v(L/2)=0$
(%i18) bc7:ev(dv-dz=0,x=L/2)$
(%i19) bc8:ev(ddv-ddz=0,x=L/2)$
(%i20)
consts:algsys([bc1,bc2,bc3,bc4,bc5,bc6,bc7,bc8],[C1,C2,C3,C4,C5,C6,C7,C8]);
(%o20) [[C1 = L/16,C2 = -L^2/32,C3 = 0,C4 = 0,C5 = -L,C6 = L^2/2,
C7 = -17*wo*L^3/128,C8 = %r1]]
Is there a reason this isn't being reported as: C8=17*wo*L^4/768 ?
(%i21) solve(ev(z(x),consts,x=L/2),%r1);
(%o21) [%r1 = 17*wo*L^4/768]
Thanks,
Pete