RD Sharma - Mathematics

Book: RD Sharma - Mathematics

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

Subject: - Class 11th

Q. No. 17 of Exercise 7.1

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17

Prove that:

tan 360 + tan 90 + tan 360 tan 90 = 1

We have 36° + 9° = 45°


tan(36° + 9°) = tan 45°


We know that



tan 36° + tan 9° = 1 – tan 36° tan 9°


tan 36° + tan 9° + tan 36° tan 9° = 1


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)