Notes

Classroom License -- for classroom instructional use only.

>> A= [1 2 3; 4 5 6; 7 8 9]

A =

1 2 3
4 5 6
7 8 9

>> log(A)

ans =

0 0.6931 1.0986
1.3863 1.6094 1.7918
1.9459 2.0794 2.1972

>> help elfun
Elementary math functions.

Trigonometric.
sin - Sine.
sind - Sine of argument in degrees.
sinh - Hyperbolic sine.
asin - Inverse sine.
asind - Inverse sine, result in degrees.
asinh - Inverse hyperbolic sine.
cos - Cosine.
cosd - Cosine of argument in degrees.
cosh - Hyperbolic cosine.
acos - Inverse cosine.
acosd - Inverse cosine, result in degrees.
acosh - Inverse hyperbolic cosine.
tan - Tangent.
tand - Tangent of argument in degrees.
tanh - Hyperbolic tangent.
atan - Inverse tangent.
atand - Inverse tangent, result in degrees.
atan2 - Four quadrant inverse tangent.
atan2d - Four quadrant inverse tangent, result in degrees.
atanh - Inverse hyperbolic tangent.
sec - Secant.
secd - Secant of argument in degrees.
sech - Hyperbolic secant.
asec - Inverse secant.
asecd - Inverse secant, result in degrees.
asech - Inverse hyperbolic secant.
csc - Cosecant.
cscd - Cosecant of argument in degrees.
csch - Hyperbolic cosecant.
acsc - Inverse cosecant.
acscd - Inverse cosecant, result in degrees.
acsch - Inverse hyperbolic cosecant.
cot - Cotangent.
cotd - Cotangent of argument in degrees.
coth - Hyperbolic cotangent.
acot - Inverse cotangent.
acotd - Inverse cotangent, result in degrees.
acoth - Inverse hyperbolic cotangent.
hypot - Square root of sum of squares.
deg2rad - Convert angles from degrees to radians.
rad2deg - Convert angles from radians to degrees.

Exponential.
exp - Exponential.
expm1 - Compute exp(x)-1 accurately.
log - Natural logarithm.
log1p - Compute log(1+x) accurately.
log10 - Common (base 10) logarithm.
log2 - Base 2 logarithm and dissect floating point number.
pow2 - Base 2 power and scale floating point number.
realpow - Power that will error out on complex result.
reallog - Natural logarithm of real number.
realsqrt - Square root of number greater than or equal to zero.
sqrt - Square root.
nthroot - Real n-th root of real numbers.
nextpow2 - Next higher power of 2.

Complex.
abs - Absolute value.
angle - Phase angle.
complex - Construct complex data from real and imaginary parts.
conj - Complex conjugate.
imag - Complex imaginary part.
real - Complex real part.
unwrap - Unwrap phase angle.
isreal - True for real array.
cplxpair - Sort numbers into complex conjugate pairs.

Rounding and remainder.
fix - Round towards zero.
floor - Round towards minus infinity.
ceil - Round towards plus infinity.
round - Round towards nearest integer.
mod - Modulus (signed remainder after division).
rem - Remainder after division.
sign - Signum.

>> sqrtm(A)

ans =

0.4498 + 0.7623i 0.5526 + 0.2068i 0.6555 - 0.3487i
1.0185 + 0.0842i 1.2515 + 0.0228i 1.4844 - 0.0385i
1.5873 - 0.5940i 1.9503 - 0.1611i 2.3134 + 0.2717i

>> E=[-1.5 -1.4 -4.5 1.4 1.2];
>> round(E)

ans =

-2 -1 -5 1 1

>> ceil(E)

ans =

-1 -1 -4 2 2

>> floor(E)

ans =

-2 -2 -5 1 1

>> min(E)

ans =

-4.5000

>> max(E)

ans =

1.4000

>> sort(E)

ans =

-4.5000 -1.5000 -1.4000 1.2000 1.4000

>> t=[0:2:20]'

t =

0
2
4
6
8
10
12
14
16
18
20

>> length(t)

ans =

11

>> g=9.81; m=68.1; cd = 0.25;
>> v=sqrt(g*m/cd)*tanh(sqrt(g*cd/m)*t)

v =

0
18.7292
33.1118
42.0762
46.9575
49.4214
50.6175
51.1871
51.4560
51.5823
51.6416

>> plot(t, v)
>> plot(t, v, 'r*-')
>> title('plot of v versus t')
>> xlabel('values t')
>> ylabel('values of v')
>> xlabel('values of t')
>> grid
>> t=0:pi/50:10*pi;
>> subplot(1, 2, 1); plot(sin(t), cos(t))
>> subplot(1, 2, 2); plot3(sin(t), cos(t), t)
>> plot(sin(t), cos(t))
>> hold on
>> plot(sin(t), cos(t), 'r*')
>> hold off
>>