Math, asked by parul7576, 11 months ago

13. @Solve for x : cos (2 sin ' x) = 5 x>0
COS​

Answers

Answered by sarimkhan112005
0

Answer:

Step-by-step explanation:

Use the double angle formula for cosine involving just the sine!

3(1 - 2sin2x) + sin x = -2  

3 - 6sin2x + sin x = -2  

Set one side equal to zero!  

0 = 6sin2x - sin x - 5  

Factor!  

0 = (6sin x + 5)(sin x - 1)  

sin x = -5/6 or sin x = 1  

sin x = 1 means x = 90o

The reference angle for the first solution is x = 56.4o Since we need the number negative, the answers are in the III and IV quadrants.

x = 180 + 56.4 = 236.4o or x = 360 - 56.4 = 303.6o  

x = 90o, 236.4o, 303.6o

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