# 5cos theta + 12sin theta=13,then find sin theta=? plz give proper explanation about this problem if anyone on online

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by nathamar370

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by nathamar370

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so 5 cosx=13-12 sinx

squaring on both sides we get,

25 cos²x=169+144 sin²x-312 sinx

in case of cos²x we substitute (1-sin²x),as sin²x+cos²x=1

equation will be 169 sin²x-312 sinx+144=0

after using quadratic formula we get sinx=312/338

so sinx =12/13.

done!!!!!!!!!!!!