We can solve this problem using the trigonometric function of Sum and Difference Compound Angles: An algebraic sum of two or more angles is called a compound angle tan (A - B) = tan A - tan B/1 + tanA tanB By using this formula we can find the answer. We have
sin79°−sin11°
sin79°+sin11°
sin79°−sin11°
sin79°+sin11°
=
cos11°−sin11°
cos11°+sin11°
(Since , sin (90 - θ) = cos θ ; sin 79° = sin (90 - 11) = cos 11°) Divide the numerator and denominator by cos 11° =