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Prove that: sin 60° = 2 sin 30° cos 30° - Mathematics

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Question

Prove that:

sin 60° = 2 sin 30° cos 30°

Theorem
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Solution

sin 60 = 2 sin 30 cos 30

`sin60^\circ = sqrt3/2`

`sin30^\circ = 1/2`

`cos 30^\circ = sqrt3/2`

`2  sin 30^\circcos^\circ = 2 xx 1/2xxsqrt3/2`

2 sin 30 cos 30 = 2 × `1/2xxsqrt3/2`

`\cancel2 xx 1/\cancel2 xx sqrt3/2 = sqrt3/2`

sin 60° = 2 sin 30° cos 30° 

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Chapter 23: Trigonometrical Ratios of Standard Angles [Including Evaluation of an Expression Involving Trigonometric Ratios] - Exercise 23 (A) [Page 291]

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Selina Concise Mathematics [English] Class 9 ICSE
Chapter 23 Trigonometrical Ratios of Standard Angles [Including Evaluation of an Expression Involving Trigonometric Ratios]
Exercise 23 (A) | Q 6.1 | Page 291
Nootan Mathematics [English] Class 9 ICSE
Chapter 18 Trigonometric Ratios of Some Standard Angles and Complementary Angles
Exercise 18A | Q 7. | Page 372
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