If cos (a+b)= 0 then sin (a+2b)=?.....solve it plz

1.	If cos (a+b)= 0 then sin (a+2b)=?.....solve it plz
Answer» Cos(a+b)=0sin(a+b)=root under1-0^2=±1sin(a+2b)=sin[(a+b)+b]sin(a+b)=1cosb+ cos(a+b)=0sinb=±cosb ans.

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