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If sec a + tan a = 3, find the value of sin a. 

If 2 sec 3x = 4, then the value of x:

Simplify the following trigonometric expression:
14 tan 25° cot 65° − 6 cos 39° sec 51°

If 4sin² θ = 3(1+ cos θ), 0° < θ < 90°, then what is the value of (2tan θ + 4sinθ - secθ)?

If SecA + TanA = 2√2 + 9, then find the value of Sin A + Cos A.

Find the value of sin²65^o + sin²25^o + cos²35^o + cos²55^o.

If cos2B = sin(1.5B + 20^o), then find the measure of 'B'.

If x = r sin A cos B, y = r sin A sin B and z = r cos A, then find x² + y² + z².