RD Sharma - Mathematics

Book: RD Sharma - Mathematics

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

Subject: - Class 11th

Q. No. 15 of Exercise 7.1

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15

prove that:

cos2 π/4 - sin2

LHS


We know that cos2A – sin2B = cos(A +B) cos(A –B)






= RHS


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)