Question

If sin3 theta = cos (theta-6°) and 3 theta and (theta-6°) are acute angles, find theta.

Answer 1

sin3@=cos(@-6)

[using sin@=cos(90-@)]

cos(90-3@)=cos(@-6)

90-3@=@-6

90+6=@+3@

96=4@

@=96/4

@=24

Answer 2

sin 3Ф = cos ( Ф - 6)

sin 3Ф = sin ( 90 - Ф + 6)  [we know, sin(90 - Ф) = cos Ф

 3Ф = 90 + 6 - Ф

3Ф + Ф = 96 

4Ф = 96 

Ф = 96/4 

Ф = 24 


i hope this will help you

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