if sin theta = -1/3 and theta does not lies in the third quadrant then cos theta =
Answers
Answered by
0
Step-by-step explanation:
sinθ=−
3
1
=>sin
2
θ=
9
1
sin
2
θ+cos
2
θ=1
9
1
+cos
2
θ=1
cos
2
θ=1−
9
1
=
9
8
cosθ=±
9
8
=±
3
2
2
=>cosθ=
3
2
2
orcosθ=−
3
2
2
Now sinθ is negative, θ must lie in 3rd or 4th quadrant.
But it is given that θ does not lie in 3rd quadrant..
So θ lies in 4th quadrant
In 4th quadrant cosθ is positive.
=>cosθ=−
3
2
2
=>cosθ=
3
2
2
Ans=
3
2
2
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