Question 1206693

a) {{{sin (A+90)}}}

{{{sin (A+90)=cos(90) sin(A) + cos(A) sin(90)}}}

{{{sin (A+90)=0* sin(A) + cos(A)*1}}}

{{{sin (A+90)= cos(A)}}}



b) {{{cos (B+270)}}}

{{{cos (B+270)=cos(270)* cos(B) - sin(270) *sin(B)}}}

{{{cos (B+270)=0*cos(B) - (-1)* sin(B)}}}

{{{cos (B+270)= sin(B)}}}



c) {{{tan (C+315)}}}


{{{tan (C+315)=sin(C+315)/cos(C+315)}}}


{{{tan (C+315)=(cos(315)* sin(C) + cos(C) *sin(315))/(cos(315) cos(C) - sin(315) sin(C))}}}


{{{tan (C+315)=((1/sqrt(2)) *sin(C) + cos(C) *(-1/sqrt(2)))/((1/sqrt(2)) cos(C) - (-1/sqrt(2)) sin(C))}}}}


{{{tan (C+315)=((sin(C) - cos(C))/sqrt(2) )/((sin(C) + cos(C))/sqrt(2))}}}


{{{tan (C+315)=(sin(C) - cos(C))/(sin(C) + cos(C))}}}