Q. 6 A5.0( 2 Votes )

If A=60o and B = 30o, verify that :

cos (A+B) = cos A cos B – sin A sin B

Answer :

Given: A=60o and B =30o

Now, LHS = Cos (A+B)

Cos (60 o + 30 o)

Cos (90 o)

0 [ cos 90 o = 0]

Now, RHS = Cos A Cos B – Sin A Sin B

cos(60 o) cos(30 o) – sin(60 o) sin (30 o)



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
Champ Quiz | Trigonometric Identities33 mins
Trigonometric Identities33 mins
NCERT | Trigonometric Identities52 mins
Quiz | Task on Trigonometric Ratios46 mins
Algebraic Identities48 mins
Quiz | Practice Important Questions on Trigonometrical Identities46 mins
Quiz on Trigonometric Ratios31 mins
T- Ratios of Specified Angles58 mins
Trick to learn all Trigonometric Formulae28 mins
Testing the T- Ratios of Specified Angles57 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