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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11

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

Exercise 7.1
Exercise 7.2
Very Short Answer
MCQ

More Exercise Questions

1

If α + β - γ = π, and sin2 α + sin2 β – sin2 γ = λ sin α sin β cos γ, then write the value of λ.
2

If then write the value of

3

Write the maximum and minimum values of 3 cos x + 4 sin x + 5.
4

Write the maximum values of 12 sin x – 9 sin2 x.
5

If 12 sin x – 9 sin2 x attains its maximum value at x = α, then write the value of sin α.
6

Write the interval in which the values of lie.
7

If tan (A + B) = p and tan (A – B) = q, then write the value of tan 2B.
8

If then write the value of tan x tan y.
9

If then write the value of ab + bc + ca.
10

If A + B = C, then write the value of tan A tan B tan C.
11

If sin α – sin β = a and cos α + cos β = b, then write the value of cos (α + β).
12

If and then write the value of α + β lying in the interval (0, π/2).

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