Advertisement Remove all ads
Advertisement Remove all ads
Advertisement Remove all ads
Sum
Prove that
sin (70° + θ) − cos (20° − θ) = 0
Advertisement Remove all ads
Solution
\[\begin{array}{l}(i) L.H.S=sin( {70}^0 + \theta) - \cos( {20}^0- \theta) \\ \end{array}\]
\[\begin{array}{l}=sin{ {90}^0 - ( {20}^0 - \theta)} - \cos( {20}^0 - \theta) \\ \end{array}\]
\[\begin{array}{l}=\cos( {20}^0 - \theta) -\cos( {20}^0 - \theta) \\ \end{array}\]
=0
= RHS
Concept: Trigonometric Ratios of Some Special Angles
Is there an error in this question or solution?
