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प्रश्न
Find the value of the following:
cosec 15º
उत्तर
cosec 15º = `1/(sin 15^circ)`
Consider sin 15° = sin(45° – 30°)
= sin 45° cos 30° – cos 45° sin 30°
`= 1/sqrt2 xx sqrt3/2 - 1/sqrt2 xx 1/2`
`= sqrt3/(2sqrt2) - 1/(2sqrt2)`
`= (sqrt3 - 1)/(2sqrt2)`
cosec 15° = `1/(sin 15^circ) = (2sqrt2)/(sqrt3 - 1)`
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