Q. 11

If sin α – sin β = a and cos α + cos β = b, then write the value of cos (α + β).

Answer :

sin α – sin β = a

cos α + cos β = b


(sin α – sin β )2= a2 …..1


(cos α + cos β)2= b2 …….2


add both equations



value of


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
Position of a Word & Sum Of NumbersPosition of a Word & Sum Of NumbersPosition of a Word & Sum Of Numbers56 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