RD Sharma - Mathematics

Book: RD Sharma - Mathematics

Chapter: 7. Values of Trigonometric Functions at Sum of Difference of Angles

Subject: Maths - Class 11th

Q. No. 11 of Very Short Answer

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

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

Chapter Exercises

More Exercise Questions


If then write the value of