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secondary 4 | A Maths
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secondary 4 chevron_right A Maths chevron_right Singapore

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Date Posted: 3 years ago
Views: 265
Eric Nicholas K
Eric Nicholas K
3 years ago
I don’t think A and B can be found without a calculator on its own.

As for sin (pi/2 - A/2), we need to use quadrants triangle and your addition and double angle formulae.

See 1 Answer

1) sine and cosine in third quadrant since both are minus

Use calculator find angle

2) sin(pi()/2-A/2) = cos(A/2)
Cos(A/2) = [(1+Cos(A))/2]^0.5

From 1), find COS(A)
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Kahwai
Kahwai's answer
232 answers (A Helpful Person)
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MM
MM
3 years ago
Thank you