RD Sharma - Mathematics

Book: RD Sharma - Mathematics

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

Subject: - Class 11th

Q. No. 11 of Exercise 7.1

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11

Prove that:

(i) (ii)


(ii)

(i) LHS


Dividing numerator And denominator by cos 11°,





We know that



= tan 56° = RHS


Hence proved.


(ii) LHS


Dividing numerator And denominator by cos 9°,





We know that



= tan 54° = RHS


Hence proved.


(iii) LHS


Dividing numerator And denominator by cos 8°,





We know that



= tan 37° = 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)