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secondary 4 | A Maths
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For 6(d), why cant the answer be 1/k? (Since 20° and 70° are in the same quad)
Date Posted: 3 years ago
Views: 212
by definition, cosec A = 1 / (sin A)
therefore, cosec 70 = 1 / (sin 70) = 1 / sqrt(1-k^2)
1/k = 1 / sin 20 = cosec 20 !!
therefore, cosec 70 = 1 / (sin 70) = 1 / sqrt(1-k^2)
1/k = 1 / sin 20 = cosec 20 !!
the same quadrant does not mean sin70 = k. It only means that the sign of the constant k will be the same for sin20 and sin70.
Ohh, but how is it different from part a? (Sin 200°=-k)
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The angle 20 and 70 are in the first quadrant and that means that sin(20) and sin(70) will both be positive. But they will have different positive values.
Date Posted:
3 years ago
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