The value of cos 60°. cos 30° - sin 60°. sin 30°=
Answers
Answered by
1
Answer:
You can do each calculation separately and do all the math, or you can recognize the angle difference formula for cosine:
cos
(
A
−
B
)
=
cos
A
×
cos
B
+
sin
A
×
sin
B
In this case,
A
is
60
∘
and
B
is
30
∘
. Use the formula backward now:
=
cos
60
∘
×
cos
30
∘
+
sin
60
∘
×
sin
30
∘
=
cos
(
60
∘
−
30
∘
)
=
cos
(
30
∘
)
=
√
3
2
We can verify our answer by doing all the calculations:
=
cos
60
∘
×
cos
30
∘
+
sin
60
∘
×
sin
30
∘
=
1
2
×
√
3
2
+
√
3
2
×
1
2
=
√
3
4
+
√
3
4
=
2
√
3
4
=
√
3
2
Similar questions