SOLUTION: If sin 3A=cos(A-26�) where 3A is an acute angle,find the value of A.

Question 1077075: If sin 3A=cos(A-26�) where 3A is an acute angle,find the value of A.
Answer by ikleyn(52781) (Show Source): You can put this solution on YOUR website!
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If sin 3A=cos(A-26�) where 3A is an acute angle,find the value of A.
~~~~~~~~~~~~~~~~~~

Use the identity  = , which is the same as cos(x) = sin(90�-x).

It gives

sin(3A) = sin(90� - A + 26�).


The last equation implies (since all the angles are in QI)

3A = 90� - A + 26�,   or

4A = 116�,

A =  = 29�.


Answer.  A = 29�.

Solved.

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