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Find the value of: 1 – 2 cos2 60° + sin 30° - Mathematics

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Question

Find the value of:

1 – 2 cos2 60° + sin 30°

Sum
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Solution

Given:

1 – 2 cos2 60° + sin 30°

Step 1: Use standard trigonometric values

`cos 60° = 1/2 → cos^2 60° = (1/2)^2 = 1/4`

Step 2: Substitute the values

= `1 − 2 ⋅ 1/4 + 1/2`

= `1 − 2/4 + 1/2`

= `1 − 1/2 + 1/2`

= 1

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Chapter 19: Trigonometry - EXERCISE 19C [Page 236]

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B Nirmala Shastry Mathematics [English] Class 9 ICSE
Chapter 19 Trigonometry
EXERCISE 19C | Q I. 4. | Page 236
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