Question

sinsin a minus b by cos a into cos b + sin a b minus c by cos b into cos c + sin c minus 1 by cos a into cos c is equal to
​

Answer 1

Answer:

bcosa

Step-by-step explanation:

ccos(A−α)+acos(C+α)=bcosα

Consider, ccos(A−α)+acos(C+α)

=ccosAcosα+csinAsinα+acosCcosα−asinCsinα

=cosα(acosC+ccosA)+sinα(csinA−asinC)

=bcosα+sinα(0)    (sinAa=sinCc)

=bcosα