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. 3 of Exercise 7.2

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3

Show that Sin 1000 – Sin 100 is positive.

Let f(x) = sin 100° – sin 10°


Dividing And multiplyingBy √(1 + 1) = √2,





We know that cosA cosB – sinA sinB = cos(A +B)



∴ f(x) = √2 cos 55°


Chapter Exercises

Exercise 7.1
Exercise 7.2
Very Short Answer
MCQ

More Exercise Questions

1

Find the maximum and minimum values of each of the following trigonometrical expressions:

(i) 12 sin x- 5 cos x


(ii) 12 cos x + 5 sin x+ 4


(iii)


(iv) sin x – cos x + 1
2

Reduce each of the following expressions to the Sine And Cosine of A single expression:
2

Reduce each of the following expressions to the Sine And Cosine ofA single expression:

cos x – sin x
2

Reduce each of the following expressions to the Sine And Cosine ofA single expression:

24 cos x + 7 sin x
3

Show that Sin 1000 – Sin 100 is positive.
4

Prove that lies between and .

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