Sin(A+B) = SinACosB + CosASinB
Cos(A+B) = CosACosB - SinASinB
Note pi is taken as pi radians = 180 degrees. Cospi = Cos180 = -1.
Sinpi = Sin 180 = 0
Cos(A+pi) = CosACospi - SinASinpi = (CosA) * (-1) - (SinA) *(0) = -CosA.
Sin(A+pi) = SinACospi + CosASinpi = (SinA)* (-1) + (CosA) * (0) = -SinA.
Cos(A+pi) - Sin(A+pi) = -CosA - -SinA = -CosA + SinA = SinA - CosA.
Answer = (a).
Please provide the complete question.
This isn't to diffuclt. So, to the formula for the area of a circle is

, or instead of r, you can put D, which is r times 2
The diameteris 2.5, so, the answer would be
pi times 2.5, where pie = 3.14
So, the answer is 2.5 * 3.14 = 7.85 or 7.9
B. Because of the slope and where it the lines intersect the y axis