Can someone help me answer this question? 'find the exact value of Cos theta, given sin theta = 5/9 and cos theta < 0
3 Answers
I got
Explanation:
Have a look:
= -0.8315 (4dp)
Explanation:
Find
The sin will also have the value
If you are not sure which of these angles will have cos < 1, try both.
(note that the numbers for both angles are actually the same but one is positive and the other is negative)
(so
Explanation:
using the trigonometric identity
∙xsin2θ+cos2θ=1
⇒cosθ=±√1−sin2θ
given sinθ=59 and cosθ<0
then θ is in the second quadrant
cosθ=−√1−(59)2
cosθ=−√1−2581
cosθ=−√5681=−√569