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Trigonometry Examples
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Trigonometry
Expand the Trigonometric Expression cos(x-y)
cos
(
x
−
y
)
cos
(
x
-
y
)
Step 1
Apply the
difference
of
angles
identity
cos
(
x
−
y
)
=
cos
(
x
)
cos
(
y
)
+
sin
(
x
)
sin
(
y
)
cos
(
x
-
y
)
=
cos
(
x
)
cos
(
y
)
+
sin
(
x
)
sin
(
y
)
.
cos
(
x
)
cos
(
y
)
+
sin
(
x
)
sin
(
y
)
cos
(
x
)
cos
(
y
)
+
sin
(
x
)
sin
(
y
)
c
o
s
(
x
−
y
)
c
o
s
(
x
-
y
)
(
(
)
)
|
|
[
[
]
]
√
√
≥
≥
°
°
7
7
8
8
9
9
≤
≤
θ
θ
4
4
5
5
6
6
/
/
^
^
×
×
>
>
π
π
1
1
2
2
3
3
-
-
+
+
÷
÷
<
<
,
,
0
0
.
.
%
%
=
=
⎡
⎢
⎣
x
2
1
2
√
π
∫
x
d
x
⎤
⎥
⎦
[
x
2
1
2
π
∫
x
d
x
]
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