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Without using tables, evaluate the following: 4(sin430° + cos460°) - 3(cos245° - sin290°). - Mathematics

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प्रश्न

Without using tables, evaluate the following: 4(sin430° + cos460°) - 3(cos245° - sin290°).

बेरीज

उत्तर

4(sin430° + cos460°) - 3(cos245° - sin290°).

sin30° = `(1)/(2)`
sin90° = 1

cos45° = `(1)/sqrt(2)`

cos60° = `(1)/(2)`
4(sin430° + cos460°) - 3(cos245° - sin290°)

= `4((1/2)^4 + (1/2)^4) -3((1/sqrt(2))^2 - (1)^2)`

= `4(1/16 + 1/16) -3(1/2 - 1)`

= `4 xx (2)/(16) + 3 xx (1)/(2)`

= `(1)/(2) + (3)/(2)`

= `(4)/(2)`
= 2.

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पाठ 27: Trigonometrical Ratios of Standard Angles - Exercise 27.1

APPEARS IN

फ्रँक Mathematics [English] Class 9 ICSE
पाठ 27 Trigonometrical Ratios of Standard Angles
Exercise 27.1 | Q 1.1

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