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secondary 3 | A Maths
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need help with this qn, pls explain too :)
Date Posted: 3 years ago
Views: 474
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done
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clear
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Since they are opposite signs, supplementary rule applies
Date Posted:
3 years ago
where did the 180 go tho
btw do we need to evaluate cos(180-160) into cos20 or we just simply remove the 180
btw do we need to evaluate cos(180-160) into cos20 or we just simply remove the 180
I rewrote 20 as 180 - 160, so that
cos 20 can be rewritten as
cos (180 - 160)
This is in the form cos (180 - x) = - cos x where x is 160.
So, we do not change the 180 - 160 back into 20 (because we started off from 20).
cos 20 can be rewritten as
cos (180 - 160)
This is in the form cos (180 - x) = - cos x where x is 160.
So, we do not change the 180 - 160 back into 20 (because we started off from 20).
thx :)
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