Question 1077075
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If sin 3A=cos(A-26°) where 3A is an acute angle,find the value of A.
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<pre>
Use the identity {{{cos(x)}}} = {{{sin(pi/2-x)}}}, 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 = {{{116/4}}} = 29°.


<U>Answer</U>.  A = 29°.
</pre>

Solved.