Answer:
sin
θ
Explanation:
∣
∣
∣
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
a
a
cos
(
A
±
B
)
=
cos
A
cos
B
∓
sin
A
sin
B
a
a
∣
∣
−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
⇒
cos
(
π
2
−
θ
)
=
cos
(
π
2
)
cos
θ
+
sin
(
π
2
)
sin
θ
now
cos
(
π
2
)
=
0
and
sin
(
π
2
)
=
1
⇒
cos
(
π
2
−
θ
)
=
0
×
cos
θ
+
1
×
sin
θ
=
sin
θ