Prove Sin(a+b)=sin(a)cos(b)+cos(a)sin(b)

if u r familiar with the proof of cos(a-b) then u can use this....
sin(a+b)=cos(Î /2-(a+b))
=cos((Î /2-a)-b)
=coa(Î /2-a)cosb+sin(Î /2-a)sinb
=sin a cos b+sin b cos a

is it usin vectors?ie cross pdt?if itz so then i can prove

Both vectors have equal magnitude A

|A₁XA₂| by components.....
gives...

A²(cosa.sinb+sina.cosb)..........................(i)

now cross product by A²sin(a+b) ...............(AB sinθ)...........(ii)

from (i) and (ii) sin(a+b)=(cosa.sinb+sina.cosb).

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yah even mine was like dis one