RD Sharma - Mathematics

Book: RD Sharma - Mathematics

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

Subject: - Class 11th

Q. No. 32 of Exercise 7.1

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32

IfAngle θ is divided into two parts such that the tangents of the one part is λ times the tangent of other, And ϕ is their difference, then show that .

Let α And β be the two parts of angle θ.


Then, given θ = α + β And ϕ = α - β


Consider tan α = λ tan β



Applying componendo And dividendo,





We know that sin(A ±B) = sinA cosB ± cosA sinB





Hence, proved.


Chapter Exercises

More Exercise Questions

6

If SinA = 1/2, cosB = , where π/2<A < π And 0 <B < π/2, find the following:

(i) tan(A +B)(ii) tan(A -B)