Answer :

LHS


= sin 480° cos 690° + cos 780° sin 1050°


= sin (90° × 5 + 30°) cos (90° × 7 + 60°) + cos (90° × 8 + 60°) sin (90° × 11 + 60°)


We know that when n is odd, sin cos and cos sin.


= cos 30° sin 60° + cos 60° [-cos 60°]



= 3/4 - 1/4


= 2/4


= 1/2


= 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
Conditional IdentitiesConditional IdentitiesConditional Identities31 mins
Trigonometric Functions - 05Trigonometric Functions - 05Trigonometric Functions - 0568 mins
Trigonometric Functions - 01Trigonometric Functions - 01Trigonometric Functions - 0152 mins
Graphs of trigonometric ratios | Trigonometric IdentitiesGraphs of trigonometric ratios | Trigonometric IdentitiesGraphs of trigonometric ratios | Trigonometric Identities39 mins
Quiz on Graph of Trigonometric RatiosQuiz on Graph of Trigonometric RatiosQuiz on Graph of Trigonometric Ratios40 mins
Trigonometric Functions - 03Trigonometric Functions - 03Trigonometric Functions - 0366 mins
Trigonometric Functions - 06Trigonometric Functions - 06Trigonometric Functions - 0658 mins
Trigonometric SeriesTrigonometric SeriesTrigonometric Series45 mins
Interactive Quiz on trigonometric ratios & identitiesInteractive Quiz on trigonometric ratios & identitiesInteractive Quiz on trigonometric ratios & identities73 mins
Trigonometric Functions - 02Trigonometric Functions - 02Trigonometric Functions - 0268 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
caricature
view all courses
RELATED QUESTIONS :

Prove that :

RD Sharma - Mathematics

prove that :

RD Sharma - Mathematics

Prove that:

RD Sharma - Mathematics

Prove that:

RD Sharma - Mathematics