m22.mws

Spreadsheet in Maple

1 Use the spreadsheet in Maple to experiment with the 3x + 1 problem.
2 How is the number pattern related to the sucessive derivatives of tan(x) formed?
3 How is the number pattern related to the sucessive derivatives of cot(x) formed?
4 Express tan(nx) as a rational function of tan(x) for n = 1,2,3,4,5,6.
5 Study the number pattern associated with the indefinite integral of the function xnex.
6 List the Chebyshev polynomials Tn(x) for n = 0,1,2,3,4,5,6.

1 Use the spreadsheet in Maple to experiment with the 3x + 1 problem.

> f:=x->if x mod 2=0 then x/2 else 3*x+1 fi;

f := proc (x) options operator, arrow; if `mod`(x,2...

>

16 17
8 52
4 26
2 13
1 40
4 20
2 10
1 5
4 16
2 8
1 4
4 2
2 1
1 4
4 2
2 1
1 4
4 2
2 1
1 4
4 2
2 1
1 4
4 2

2 How is the number pattern related to the sucessive derivatives of tan(x) formed?

>

1 1+tan(x)^2 1+u^2
2 2*tan(x)+2*tan(x)^3 2*u+2*u^3
3 2+8*tan(x)^2+6*tan(x)^4 2+8*u^2+6*u^4
4 16*tan(x)+40*tan(x)^3+24*tan(x)^5 16*u+40*u^3+24*u^5
5 16+136*tan(x)^2+240*tan(x)^4+120*tan(x)^6
16+136*tan(x)^2+240*tan(x)^4+120*tan(x)^6
16+136*u^2+240*u^4+120*u^6
6 272*tan(x)+1232*tan(x)^3+1680*tan(x)^5+720*tan(x)^7...
272*tan(x)+1232*tan(x)^3+1680*tan(x)^5+720*tan(x)^7...
272*u+1232*u^3+1680*u^5+720*u^7

3 How is the number pattern related to the sucessive derivatives of cot(x) formed?

>

1 -1-cot(x)^2 -1-u^2
2 2*cot(x)+2*cot(x)^3 2*u+2*u^3
3 -2-8*cot(x)^2-6*cot(x)^4 -2-8*u^2-6*u^4
4 16*cot(x)+40*cot(x)^3+24*cot(x)^5 16*u+40*u^3+24*u^5
5 -16-136*cot(x)^2-240*cot(x)^4-120*cot(x)^6
-16-136*cot(x)^2-240*cot(x)^4-120*cot(x)^6
-16-136*u^2-240*u^4-120*u^6
6 272*cot(x)+1232*cot(x)^3+1680*cot(x)^5+720*cot(x)^7...
272*cot(x)+1232*cot(x)^3+1680*cot(x)^5+720*cot(x)^7...
272*u+1232*u^3+1680*u^5+720*u^7

4 Express tan(nx) as a rational function of tan(x) for n = 1,2,3,4,5,6.

>

1 tan(x)
2 2*tan(x)/(1-tan(x)^2)
3 (3*tan(x)-tan(x)^3)/(1-3*tan(x)^2)
4 (4*tan(x)-4*tan(x)^3)/(1-6*tan(x)^2+tan(x)^4)
5 (5*tan(x)-10*tan(x)^3+tan(x)^5)/(1-10*tan(x)^2+5*ta...
6 (6*tan(x)-20*tan(x)^3+6*tan(x)^5)/(1-15*tan(x)^2+15...

5 Study the number pattern associated with the indefinite integral of the function xnex.

>

1 exp(x)*(x-1)
2 exp(x)*(x^2-2*x+2)
3 exp(x)*(x^3-3*x^2+6*x-6)
4 exp(x)*(x^4-4*x^3+12*x^2-24*x+24)
5 exp(x)*(x^5-5*x^4+20*x^3-60*x^2+120*x-120)
exp(x)*(x^5-5*x^4+20*x^3-60*x^2+120*x-120)
6 exp(x)*(x^6-6*x^5+30*x^4-120*x^3+360*x^2-720*x+720)...
exp(x)*(x^6-6*x^5+30*x^4-120*x^3+360*x^2-720*x+720)...

6 List the Chebyshev polynomials Tn(x) for n = 0,1,2,3,4,5,6.

>

0 1
1 cos(x)
2 2*cos(x)^2-1
3 4*cos(x)^3-3*cos(x)
4 8*cos(x)^4-8*cos(x)^2+1
5 16*cos(x)^5-20*cos(x)^3+5*cos(x)
6 32*cos(x)^6-48*cos(x)^4+18*cos(x)^2-1


Factoring

1 Find an exponent n such that some coefficients appearing in the factorization of xn - 1 are different from 0, -1 and
1.
Reference: 吳振奎,數學中的美--數學美學初探,天津教育,(1996), p. 143.

> factor(x^99-1);

(x-1)*(x^10+x^9+x^8+x^7+x^6+x^5+x^4+x^3+x^2+x+1)*(x...
(x-1)*(x^10+x^9+x^8+x^7+x^6+x^5+x^4+x^3+x^2+x+1)*(x...
(x-1)*(x^10+x^9+x^8+x^7+x^6+x^5+x^4+x^3+x^2+x+1)*(x...

>

Factor (((x2 - a)2 - a)2 - a)2 - a - x.
Reference: Ramanujan's Notebooks IV, p. 42.

> restart:

> factor((x^2-a)^2-a-x);

(a-x^2+x)*(a-x^2-1-x)

> factor((((x^2-a)^2-a)^2-a)^2-a-x);

(a-x^2+x)*(a-x^2-1-x)*(1+2*a^2+x^12+x^6-x^2*a+4*x^3...
(a-x^2+x)*(a-x^2-1-x)*(1+2*a^2+x^12+x^6-x^2*a+4*x^3...
(a-x^2+x)*(a-x^2-1-x)*(1+2*a^2+x^12+x^6-x^2*a+4*x^3...

>