1.1
a = 3; b = 5; sum = a + b; difference = a - b; product = a * b; quotient = a / b;
2.1
(a) Comma should be replaced by decimal point
(e) Asterisk should be omitted
(f) Exponent must be integer
(h) Comma should be replaced by decimal point
2.2
(b) Decimal point not allowed
(c) First character must be letter
(d) Quotes not allowed
(h) Blanks not allowed
(i) Allowed but not recommended
(k) Asterisk not allowed
(l) Allowed but not recommended
2.3
(a) p + w/u
(b) p + w/(u + v)
(c) (p + w/(u+v))/(p + w/(u-v))
(d) sqrt(x)
(e) y^(y+z)
(f) x^(y^z)
(g) (x^y)^z
(h) x - x^3/(3*2) + x^5/(5*4*3*2)
2.4
(a) i = i + 1
(b) i = î3 + j
(c)
if e > f g = e else g = f end
(d)
if d > 0 x = -b end
(e) x = (a + b)/(c * d)
2.5
(a) Expression not allowed on left-hand side
(b) Left-hand side must be valid variable name
(c) Left-hand side must be valid variable name
2.6
a = 2; b = -10; c = 12; x = (-b + sqrt(b ^ 2 - 4 * a * c)) / (2 * a)
2.7
gallons = input('Enter gallons: '); pints = input('Enter pints: '); pints = pints + 8 * gallons; litres = pints / 1.76
2.8
distance = 528; litres = 46.23; kml = distance / litres; l100km = 100 / kml; disp( 'Distance Litres used km/L L/100km' ); disp( [distance litres kml l100km] );
2.9
t = a; a = b; b = t;
2.10
a = [a b]; % make 'a' into a vector b = a(1); a(1) = [];
2.11
(a)
c = input('Enter Celsius temperature: '); f = 9 * c / 5 + 32; disp( ['The Fahrenheit temperature is:' num2str(f)] );
(b)
c = 20 : 30; f = 9 * c / 5 + 32; format bank; disp(' Celsius Fahrenheit'); disp([c' f']);
2.12
degrees = 0 : 10 : 360; radians = degrees / 180 * pi; format bank; disp(' Degrees Radians'); disp([degrees' radians']);
2.13
degrees = 0 : 30 : 360; radians = degrees / 180 * pi; sines = sin(radians); cosines = cos(radians); tans = tan(radians); table = [degrees' sines' cosines' tans']
2.14
for int = 10 : 20 disp( [int sqrt(int)] ); end
2.15
sum(2 : 2 : 200)
2.16
m = [5 8 0 10 3 8 5 7 9 4]; disp( mean(m) )
2.17
x = 2.0833, a = 4
2.18
% With for loop i = 1; x = 0; for a = i : i : 4 x = x + i / a; end % With vectors i = 1; a = i : i : 4; x = i ./ a; sum(x)
2.19
(b)
n = input('Number of terms? '); k = 1 : n; s = 1 ./ (k .char136 2); disp(sqrt(6 * sum(s)))
2.21
r = 5; c = 10; l = 4; e = 2; w = 2; i = e / sqrt(r ^ 2 + (2 * pi * w * l - 1 / (2 * pi * w * c)) ^ 2)
2.22
con = [200 500 700 1000 1500]; for units = con if units <= 500 cost = 0.02 * units; elseif units <= 1000 cost = 10 + 0.05 * (units - 500); else cost = 35 + 0.1 * (units - 1000); end charge = 5 + cost; disp( charge ) end
2.24
money = 1000; for month = 1 : 12 money = money * 1.01; end
2.26
t = 1790 : 10 : 2000; p = 197273000 ./ (1 + exp(-0.03134 * (t - 1913.25))); disp([t' p']); pause; plot(t,p);
2.27
(a)
r = 0.15; l = 50000; n = 20; p = r * l * (1 + r / 12) ^ (12 * n) / ... (12 * ((1 + r / 12) ^ (12 * n) 1))
2.28
(a)
r = 0.15; l = 50000; p = 800; n = log(p / (p - r * l / 12)) / (12 * log(1 + r / 12))
3.1 You should get a picture of tangents to a curve.
3.2
(a) 4
(b) 2
(c) Algorithm (attributed to Euclid) finds the HCF (highest common factor) of two numbers using the fact that it divides exactly into the difference between the two numbers, and that, if the numbers are equal, they are equal to their HCF.
3.3
f = input('Enter Fahrenheit temperature: '); c = 5 / 9 * (f {minuscda} 32); disp( ['The Celsius temperature is: ' num2str(c)] );
3.4
a = input('Enter first number: '); b = input('Enter second number: '); if a < b disp( [ num2str(b) ' is larger.'] ); elseif a > b disp( [ num2str(a) ' is larger.'] ); else disp( 'Numbers are equal.' ); end
3.6 1. Input a, b, c, d, e, f
2. u = ae - db, v = ec - bf
3. If u = 0 and v = 0, then
Lines coincide
Otherwise if u = 0 and , then
Lines are parallel
Otherwise
x = v/u, y = (af - dc)/u
Print x, y
4. Stop
a = input('Enter a: '); b = input('Enter b: '); c = input('Enter c: '); d = input('Enter d: '); e = input('Enter e: '); f = input('Enter f: '); u = a * e - b * d; v = c * e - b * f; if u == 0 if v == 0 disp('Lines coincide.'); else disp('Lines are parallel.'); end else x = v / u; y = (a * f - d * c) / u; disp( [x y] ); end
4.2
(a) log(x + x ^ 2 + a ^ 2)
(b) (exp(3 * t) + t ̂ 2 * sin(4 * t)) * (cos(3 * t)) ̂ 2
(c) 4 * atan(1)
(d) sec(x)̂2 + cot(x)
(e) atan(a / x)
4.3
m = input('Enter length in metres: '); inches = m * 39.37; feet = fix(inches / 12); inches = rem(inches, 12); yards = fix(feet / 3); feet = rem(feet, 3); disp( [yards feet inches] );
4.5
a = 10; x = 1; k = input('How many terms do you want? '); for n = 1 : k x = a * x / n; if rem(n, 10) == 0 disp( [n x] ); end end
4.6
secs = input('Enter seconds: '); mins = fix(secs / 60); secs = rem(secs, 60); hours = fix(mins / 60); mins = rem(mins, 60); disp( [hours mins secs] );
5.2
(a) 1 1 0
(b) 0 1 0
(c) 1 0 1
(d) 0 1 1
(e) 1 1 1
(f) 0 0 0
(g) 0 2
(h) 0 0 1
5.3
neg = sum(x < 0); pos = sum(x > 0); zero = sum(x == 0);
5.7
units = [200 500 700 1000 1500]; cost = 10 * (units > 500) + 25 * (units > 1000) + 5; cost = cost + 0.02 * (units <= 500) .* units; cost = cost + 0.05 * (units > 500 & units <= 1000) .* (units - 500); cost = cost + 0.1 * (units > 1000) .* (units - 1000);
6.6
function x = mygauss(a, b) n = length(a); a(:,n+1) = b; for k = 1:n a(k,:) = a(k,:)/a(k,k); % pivot element must be 1 for i = 1:n if i ~= k a(i,:) = a(i,:) - a(i,k) * a(k,:); end end end % solution is in column n+1 of a: x = a(:,n+1);
7.1
function pretty(n, ch) line = char(double(ch)*ones(1,n)); disp(line)
7.2
function newquot(fn) x = 1; h = 1; for i = 1 : 10 df = (feval(fn, x + h) - feval(fn, x)) / h; disp( [h, df] ); h = h / 10; end
7.3
function y = double(x) y = x * 2;
7.4
function [xout, yout] = swop(x, y) xout = y; yout = x;
7.6
% Script file for i = 0 : 0.1 : 4 disp( [i, phi(i)] ); end % Function file phi.m function y = phi(x) a = 0.4361836; b = -0.1201676; c = 0.937298; r = exp(-0.5 * x * x) / sqrt(2 * pi); t = 1 / (1 + 0.3326 * x); y = 0.5 - r * (a * t + b * t * t + c * t ^ 3);
7.8
function y = f(n) if n > 1 y = f(n - 1) + f(n - 2); else y = 1; end
8.1
balance = 1000; for years = 1 : 10 for months = 1 : 12 balance = balance * 1.01; end disp( [years balance] ); end
8.2
(a)
terms = 100; pi = 0; sign = 1; for n = 1 : terms pi = pi + sign * 4 / (2 * n - 1); sign = sign * (-1); end
(b)
terms = 100; pi = 0; for n = 1 : terms pi = pi + 8 / ((4 * n - 3) * (4 * n - 1)); end
8.3
a = 1; n = 6; for i = 1 : 10 n = 2 * n; a = sqrt(2 - sqrt(4 - a * a)); l = n * a / 2; u = l / sqrt(1 - a * a / 2); p = (u + l) / 2; e = (u - l) / 2; disp( [n, p, e] ); end
8.5
x = 0.1; for i = 1 : 7 e = (1 + x) ^ (1 / x); disp( [x, e] ); x = x / 10; end
8.6
n = 6; T = 1; i = 0; for t = 0:0.1:1 i = i + 1; F(i) = 0; for k = 0 : n F(i) = F(i) + 1 / (2 * k + 1) * sin((2 * k + 1) * pi * t / T); end F(i) = F(i) * 4 / pi; end t = 0:0.1:1; disp( [t' F'] ) plot(t, F)
8.8
sum = 0; terms = 0; while (sum + terms) <= 100 terms = terms + 1; sum = sum + terms; end disp( [terms, sum] );
8.10
m = 44; n = 28; while m ~= n while m > n m = m - n; end while n > m n = n - m; end end disp(m);
9.1
t = 1790:2000; P = 197273000 ./ (1+exp(-0.03134*(t-1913.25))); plot(t, P), hold, xlabel('Year'), ylabel('Population size') census = [3929 5308 7240 9638 12866 17069 23192 31443 38558 ... 50156 62948 75995 91972 105711 122775 131669 150697]; census = 1000 * census; plot(1790:10:1950, census, 'o'), hold off
9.2
a = 2; q = 1.25; th = 0:pi/40:5*pi; subplot(2,2,1) plot(a*th.*cos(th), a*th.*sin(th)), ... title('(a) Archimedes') % or use polar subplot(2,2,2) plot(a/2*q.^th.*cos(th), a/2*q.^th.*sin(th)), ... title('(b) Logarithmic') % or use polar
9.4
n=1:1000; d = 137.51; th = pi*d*n/180; r = sqrt(n); plot(r.*cos(th), r.*sin(th), 'o')
9.6
y(1) = 0.2; r = 3.738; for k = 1:600 y(k+1) = r*y(k)*(1 - y(k)); end plot(y, '.w')
11.1
x = 2; h = 10; for i = 1 : 20 h = h / 10; dx = ((x + h) ^ 2 - x * x) / h; disp( [h, dx] ); end
13.1
heads = rand(1, 50) < 0.5; tails = ~heads; heads = heads * double('H'); tails = tails * double('T'); coins = char(heads + tails)
13.2
bingo = 1 : 99; for i = 1 : 99 temp = bingo(i); swop = floor(rand * 99 + 1); bingo(i) = bingo(swop); bingo(swop) = temp; end for i = 1 : 10 : 81 disp(bingo(i : i + 9)) end disp(bingo(91 : 99))
13.4
circle = 0; square = 1000; for i = 1 : square x = 2 * rand - 1; y = 2 * rand - 1; if (x * x + y * y) < 1 circle = circle + 1; end end disp( circle / square * 4 );
14.1
(a) Real roots at 1.856 and −1.697; complex roots at
(b) 0.589, 3.096, 6.285, … (roots get closer to multiples of π)
(c) 1, 2, 5
(d) 1.303
(e) −3.997, 4.988, 2.241, 1.768
14.2 Successive bisections: 1.5, 1.25, 1.375, 1.4375, and 1.40625 (exact answer: 1.414214 …, so the last bisection is within the required error)
14.3 22 (exact answer: 21.3333)
14.4 After 30 years, exact answer: 2 117 ()
14.6 The differential equations to be solved are
The exact solution after 8 hours is and .
14.8
function s = simp(f, a, b, h) x1 = a + 2 * h : 2 * h : b {minuscda} 2 * h; sum1 = sum(feval(f, x1)); x2 = a + h : 2 * h : b {minuscda} h; sum2 = sum(feval(f, x2)); s = h / 3 * (feval(f, a) + feval(f, b) + 2 * sum1 + 4 * sum2);
With 10 intervals (), luminous efficiency is 14.512725%. With 20 intervals, it is 14.512667%. These results justify the use of 10 intervals in any further computations. This is a standard way to test the accuracy of a numerical method: halve the step-length and see how much the solution changes.
14.9
% Command Window beta = 1; ep = 0.5; [t, x] = ode45(@vdpol, [0 20], [0; 1], [], beta, ep); plot(x(:,1), x(:,2)) % Function file vdpol.m function f = vdpol(t, x, b, ep) f = zeros(2,1); f(1) = x(2); f(2) = ep * (1 - x(1)^2) * x(2) - b^2 * x(1);
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