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sin2cos2

Sin2cos2 refers to the product sin(2) cos(2), i.e., the sine and cosine of the same angle measured in a given unit. A standard trigonometric identity says that sin x cos x = (1/2) sin(2x). Applying this with x = 2 gives sin 2 cos 2 = (1/2) sin 4. The value depends on the angular unit: if the numbers are in radians, sin 4 ≈ -0.7568, so sin 2 cos 2 ≈ -0.3784. If the numbers are in degrees, sin 4° ≈ 0.06976, and sin 2° cos 2° ≈ 0.03488, which equals (1/2) sin 4°.

General properties include that sin x cos x is bounded between -1/2 and 1/2, since |sin x

Related topics include product-to-sum formulas, which convert products of sine and cosine into sums of sines,

cos
x|
≤
1/2
with
equality
when
x
=
π/4
+
kπ.
The
identity
sin
x
cos
x
=
(1/2)
sin
2x
also
shows
the
expression
is
a
rescaled
sine
wave
as
x
varies,
with
period
π
in
radians
(or
180°
in
degrees).
and
their
use
in
simplifying
trigonometric
expressions,
Fourier
analysis,
and
signal
processing.
The
specific
case
sin
2
cos
2
is
a
simple
illustration
of
how
a
product
can
be
rewritten
as
a
single
sine
function
of
a
doubled
angle,
revealing
both
algebraic
relationships
and
numeric
evaluations.