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Tardigrade
Question
Mathematics
Let S= θ ∈[0,2 π): tan (π cos θ)+ tan (π sin θ)=0 . Then displaystyle∑θ ∈ s sin 2(θ+(π/4)) is equal to
Q. Let
S
=
{
θ
∈
[
0
,
2
π
)
:
tan
(
π
cos
θ
)
+
tan
(
π
sin
θ
)
=
0
}
.
Then
θ
∈
s
∑
sin
2
(
θ
+
4
π
)
is equal to _______
1086
146
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JEE Main 2023
Trigonometric Functions
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Answer:
2
Solution:
tan
(
π
cos
θ
)
+
tan
(
π
sin
θ
)
=
0
tan
(
π
cos
θ
)
=
−
tan
(
π
sin
θ
)
tan
(
π
cos
θ
)
=
tan
(
−
π
sin
θ
)
π
cos
θ
=
nπ
−
π
sin
θ
sin
θ
+
cos
θ
=
n
where
n
∈
I
possible values are
n
=
0
,
1
and
−
1
because
−
2
≤
sin
θ
+
cos
θ
≤
2
Now it gives
θ
∈
{
0
,
2
π
,
4
3
π
,
4
7
π
,
2
3
π
,
π
}
So
θ
∈
S
∑
sin
2
(
θ
+
4
π
)
=
2
(
0
)
+
4
(
2
1
)
=
2