MATLAB Function Reference Volume 1: A - E - Bad Request

cos, cosh
2cos, cosh
Purpose Cosine and hyperbolic cosine
Syntax Y = cos(X)
Y = cosh(X)
Description The cos and cosh functions operate element-wise on arrays. The functions’
domains and ranges include complex values. All angles are in radians.
2-340
Y = cos(X) returns the circular cosine for each element of X.
Y = cosh(X) returns the hyperbolic cosine for each element of X.
Examples Graph the cosine function over the domain – π ≤ x ≤ π, and the hyperbolic
cosine function over the domain – 5 ≤ x ≤ 5.
y=cos(x)
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
x = -pi:0.01:pi; plot(x,cos(x))
x = -5:0.01:5; plot(x,cosh(x))
-1
-4 -3 -2 -1 0
x
1 2 3 4
y=cosh(x)
0
-5 -4 -3 -2 -1 0
x
1 2 3 4 5
The expression cos(pi/2) is not exactly zero but a value the size of the
floating-point accuracy, eps, because pi is only a floating-point approximation
to the exact value of π
.
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