Q. 2

# Prove that:4(cos310o + sin320o) = 3 (cos10o + sin20o)

We know that sin (3× 20°)=cos (3× 10°)

3sin 20°–4sin320°=4cos310°–3cos 10°

(as sin 3θ=3sin θ–4sin3 θ and cos 3θ =4cos3θ–3cosθ)

4(cos310°+sin320°)=3(sin 20°+cos 10°)

LHS=RHS

Hence proved

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos  Trigonometric Ratios of Sub Angles35 mins  Trigonometric Functions - 0568 mins  Trigonometry ratios of allied angles | Interactive Quiz38 mins  Trigonometric Functions - 0152 mins  Quiz on Graph of Trigonometric Ratios40 mins  Graphs of trigonometric ratios | Trigonometric Identities39 mins  Trigo ratios for compound angles48 mins  Conditional Identities31 mins  Transformation formula in compound angles | Interactive Quiz37 mins  Quiz - Trigonometric Ratios of Sub Angles33 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses 