Derivative

"12X^3+piX^(1/2)+5.6X^7.89->Str1
0->dim(L2
0->dim(L1
0->dim(L3
0->dim(L4
Str1+"+->Str1
1->A
1->B
Repeat B=length(Str1
For(P,1,3
For(T,1,2
inString(Str1,sub("^+",T,1),B->B
Pause Expr(sub(Str1,A,B-A-(T=1)
If T=1
Ans->L3(1+dim(L3
If T=2
Ans->L4(1+dim(L4
End
End
{0,1->L1
While L1(1)
CAns+E->L2
LinReg(ax+b) {Y1}
Equ>String({Y1},Str2
Str3+Str2->Str3
B+1->A

End