HOWAR_EGN1007_CH11.m

%% Problem 1

a = [15 3 22; 3 8 5; 14 3 82];
b = [1; 5; 6];
c = [12 18 5 2];

d = a(: , 3)

e = [b d]

f = [b; d]

g = [a; c(1:3)]

%% Problem 2

thermo_scores=[  1 68 45 92;
                 2 83 54 93;
                 3 61 67 91;
                 4 70 66 92;
                 5 75 68 96;
                 6 82 67 90;
                 7 57 65 89;
                 8  5 69 89;
                 9 76 62 97;
                10 85 52 94;
                11 62 34 87;
                12 71 45 85;
                13 96 56 45;
                14 78 65 87;
                15 76 43 97;
                16 68 76 95;
                17 72 65 89;
                18 75 67 88;
                19 83 68 91;
                20 93 90 92];

student_5 = thermo_scores(5 , :)

test_1 = thermo_scores(: , 2)

std1 = std(thermo_scores(: , 2))
std2 = std(thermo_scores(: , 3))
std3 = std(thermo_scores(: , 4))

s1score = sum(thermo_scores(1 , 2:4));
s1p = mean(thermo_scores(1 , 2:4));
s2score = sum(thermo_scores(2 , 2:4));
s2p = mean(thermo_scores(2 , 2:4));
s3score = sum(thermo_scores(3 , 2:4));
s3p = mean(thermo_scores(3 , 2:4));
s4score = sum(thermo_scores(4 , 2:4));
s4p = mean(thermo_scores(4 , 2:4));
s5score = sum(thermo_scores(5 , 2:4));
s5p = mean(thermo_scores(5 , 2:4));
s6score = sum(thermo_scores(6 , 2:4));
s6p = mean(thermo_scores(6 , 2:4));
s7score = sum(thermo_scores(7 , 2:4));
s7p = mean(thermo_scores(7 , 2:4));
s8score = sum(thermo_scores(8 , 2:4));
s8p = mean(thermo_scores(8 , 2:4));
s9score = sum(thermo_scores(9 , 2:4));
s9p = mean(thermo_scores(9 , 2:4));
s10score = sum(thermo_scores(10 , 2:4));
s10p = mean(thermo_scores(10 , 2:4));
s11score = sum(thermo_scores(11 , 2:4));
s11p = mean(thermo_scores(11 , 2:4));
s12score = sum(thermo_scores(12 , 2:4));
s12p = mean(thermo_scores(12 , 2:4));
s13score = sum(thermo_scores(13 , 2:4));
s13p = mean(thermo_scores(13 , 2:4));
s14score = sum(thermo_scores(14 , 2:4));
s14p = mean(thermo_scores(14 , 2:4));
s15score = sum(thermo_scores(15 , 2:4));
s15p = mean(thermo_scores(15 , 2:4));
s16score = sum(thermo_scores(16 , 2:4));
s16p = mean(thermo_scores(16 , 2:4));
s17score = sum(thermo_scores(17 , 2:4));
s17p = mean(thermo_scores(17 , 2:4));
s18score = sum(thermo_scores(18 , 2:4));
s18p = mean(thermo_scores(18 , 2:4));
s19score = sum(thermo_scores(19 , 2:4));
s19p = mean(thermo_scores(19 , 2:4));
s20score = sum(thermo_scores(20 , 2:4));
s20p = mean(thermo_scores(20 , 2:4));

score = [s1score , s2score , s3score , s4score , s5score , s6score , s7score , s8score , s9score , s10score , s11score , s12score , s13score , s14score , s15score , s16score , s17score , s18score , s19score , s20score];
percent = [s1p , s2p , s3p , s4p , s5p , s6p , s7p , s8p , s9p , s10p , s11p , s12p , s13p , s14p , s15p , s16p , s17p , s18p , s19p , s20p];

thermo_scores2 = [thermo_scores , score' , percent']

thermo_scores3 = sortrows(thermo_scores2 , -6)

%% Problem 18

A = [-2 1 ; 1 1];
B = [3 ; 10];
Prob_18a_Method1 = (A \ B)
Prob_18a_Method2 = inv(A) * B

A = [5 3 4 ; 3 2 -1 ; -1 1 3];
B = [10 ; 4 ; 12];
Prob_18b_Method1 = (A \ B)
Prob_18b_Method2 = inv(A) * B

A = [3 1 2 1 ; 1 -3 2 1 ; 1 7 -3 1 ; 1 1 4 1];
B = [24 ; 12 ; 17 ; 0];
Prob_18c_Method1 = (A \ B)
Prob_18c_Method2 = inv(A) * B

%% Problem 19

A = [3 2 1 5 3 -2 1 ; 4 -2 2 10 2 9 -2 ; 2 3 3 4 -2 1 -8 ; -1 -4 1 3 -4 3 4 ; 1 5 2 9 -5 -3 2 ; 7 2 4 -2 -6 5 4 ; 1 8 6 1 7 1 5];
B = [42 ; 32 ; 12 ; -5 ; 10 ; 18 ; 17];

tic
Prob_19_Method1 = (A \ B)
Prob_19_Method1_Timer = toc

tic
Prob_19_Method2 = inv(A) * B
Prob_19_Method2_Timer = toc