Q3 of 48 Page 86

Find the values of the following:

(i) sin 70° sin 20° – cos 20° cos 70°


(ii)

(i) Sin (90˚ – 20˚)sin 20˚ – cos 20˚ cos 70˚


⇒ cos 20˚ sin (90˚ – 70˚) – cos 20˚cos 70˚


⇒ cos 20˚cos 70˚ – cos 20˚cos 70˚


⇒ 0.


(ii)


⇒


⇒ 2 – 1 –


⇒


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1

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(i)


(ii)


(iii)


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2

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(iii)


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 4

Find the values of the following:

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5

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