# 기초수학실습01/14-정수지

## 1978 days 전, suziejjang 작성

[-9,-7..30]
 [-9, -7, -5, -3, -1, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29] [-9, -7, -5, -3, -1, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29]
[-18,-15..100]
 [-18, -15, -12, -9, -6, -3, 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99] [-18, -15, -12, -9, -6, -3, 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99]
[a.is_prime() for a in [1..100]]
 [False, True, True, False, True, False, True, False, False, False, True, False, True, False, False, False, True, False, True, False, False, False, True, False, False, False, False, False, True, False, True, False, False, False, False, False, True, False, False, False, True, False, True, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, True, False, False, False, False, False, True, False, False, False, True, False, True, False, False, False, False, False, True, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, False, False, True, False, False, False] [False, True, True, False, True, False, True, False, False, False, True, False, True, False, False, False, True, False, True, False, False, False, True, False, False, False, False, False, True, False, True, False, False, False, False, False, True, False, False, False, True, False, True, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, True, False, False, False, False, False, True, False, False, False, True, False, True, False, False, False, False, False, True, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, False, False, True, False, False, False]
b=[] for a in [1..100] : if a.is_prime(): b.append(a) print b
 [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97] [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]
P(x)=(x-2)^3*(x^2-4*x+3)*2 P(x)
 2*(x^2 - 4*x + 3)*(x - 2)^3 2*(x^2 - 4*x + 3)*(x - 2)^3
expand(P(x))
 2*x^5 - 20*x^4 + 78*x^3 - 148*x^2 + 136*x - 48 2*x^5 - 20*x^4 + 78*x^3 - 148*x^2 + 136*x - 48
factor(P(x))
 2*(x - 1)*(x - 2)^3*(x - 3) 2*(x - 1)*(x - 2)^3*(x - 3)
(P(x)/(x-1))
 2*(x^2 - 4*x + 3)*(x - 2)^3/(x - 1) 2*(x^2 - 4*x + 3)*(x - 2)^3/(x - 1)
(P(x)/(x-1)).simplify_full()
 2*x^4 - 18*x^3 + 60*x^2 - 88*x + 48 2*x^4 - 18*x^3 + 60*x^2 - 88*x + 48
W.<x>=QQ[] W(P(x)).quo_rem(x^2-5*x+1)
 (2*x^3 - 10*x^2 + 26*x - 8, 70*x - 40) (2*x^3 - 10*x^2 + 26*x - 8, 70*x - 40)
(2*x^3 - 10*x^2 + 26*x - 8)*(x^2-5*x+1)+70*x-40
 2*x^5 - 20*x^4 + 78*x^3 - 148*x^2 + 136*x - 48 2*x^5 - 20*x^4 + 78*x^3 - 148*x^2 + 136*x - 48
var('x, y') solve( [3*x - y == 2, -2*x -y == 1 ], x,y)
 [[x == (1/5), y == (-7/5)]] [[x == (1/5), y == (-7/5)]]
solve( [ 2*x + y == -1 , -4*x - 2*y == 2],x,y)
 [[x == -1/2*r5 - 1/2, y == r5]] [[x == -1/2*r5 - 1/2, y == r5]]
solve( [ 2*x + y == -1 , -4*x - 2*y == 0],x,y)
 [] []
var('z') solve([ 2*x + 3*y + 5*z == 1, 4*x + 6*y + 10*z == 2, 6*x + 9*y + 15*z == 3], x,y,z)
 [[x == -5/2*r18 - 3/2*r19 + 1/2, y == r19, z == r18]] [[x == -5/2*r18 - 3/2*r19 + 1/2, y == r19, z == r18]]
solve(x^3-x == 7*x^2-7,x)
 [x == 7, x == -1, x == 1] [x == 7, x == -1, x == 1]
var('t') solve(abs(t-7)>=3 , t)
 #0: solve_rat_ineq(ineq=abs(t-7) >= 3) [[t == 10], [t == 4], [t < 4], [10 < t]] #0: solve_rat_ineq(ineq=abs(t-7) >= 3) [[t == 10], [t == 4], [t < 4], [10 < t]]
solve([2*x+7==17,x-3*y==-16],x,y)
 [[x == 5, y == 7]] [[x == 5, y == 7]]
f(x) = sin(x) g(x) = cos(x) p = plot(f(x), (x, 0, 2*pi), color='red') + plot(g(x), (x, 0, 2*pi), color='green') p.show()
p = plot(f(x), (x,0, 2*pi), axes_labels=['x','sin(x)'], color='purple') p.show()
p = plot(f(x), (x,0, 2*pi), linestyle='--', thickness=3) p.show()
f(x) = (x^3 + x^2 + x)/(x^2 - x -2 ) p = plot(f(x), (x, -5,5)) p.show(xmin=-2, xmax=4, ymin=-20, ymax=20)
p = plot(sin(pi*x-pi), (x,-1, 1), thickness=3, color='red') p.show()
p = plot(cos(pi*x-pi), (x,-1, 1), thickness=3, color='blue') p.show()
p1 = plot(sin(pi*x-pi), (x,-1, 1), thickness=3, color='red') p2 = plot(cos(pi*x-pi), (x,-1, 1), thickness=3, color='blue') show(p1+p2)
P(x)=2*x^3+3*x^2-5*x-6 solve(P(x)==0, x)
 [x == -2, x == -1, x == (3/2)] [x == -2, x == -1, x == (3/2)]
plot(P(x), (x, -4, 4), ymax=20, ymin=-20)
P(x)=4*x^4++4*x^3-9*x^2-x+2 solve(P(x)==0, x)
 [x == (1/2), x == -2, x == 1, x == (-1/2)] [x == (1/2), x == -2, x == 1, x == (-1/2)]
plot(P(x), (x, -3, 3), ymax=20, ymin=-20)
f(x)=2/(x-5) plot(f(x), (x, 2, 7), ymax=10, ymin=-10)
f(x)=-4/((x-4)^2) plot(f(x), (x, 2, 7), ymax=10, ymin=-20)
f(x)=(2*x^2+1)/(x^2-4*x+3) plot(f(x), (x, -2, 6), ymax=20, ymin=-20)
f(x)=(2*x^2-1)/(x^2+1) plot(f(x), (x, -6, 6), ymax=3)+plot(2, (x, -6, 6), color='red')
f(x)=(x^2-4)/(x-2) plot(f(x), (x, -6, 6))
f(x)=(x+2)/(x^2-x-6) plot(f(x), (x, -4, 6), ymax=20, ymin=-20)
plot(P(1/x), (x, -1, 1), ymax=10, ymin=-10)
x,y = var("x y") f(x,y) = x^2 - y^2 p = plot3d(f(x,y), (x,-10,10), (y,-10,10)) p.show()
 Sleeping...