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).
Answer:
Step-by-step explanation:
Let <em>h</em> represent the cost of hot dogs and <em>p</em> represent the cost of potato chips.
Customer 1: 4h + 5p = 15.50 ⇒ 3(4h + 5p = 15.50) ⇒ 12h + 15p = 46.50
Customer 2: 3h + 2p = 9.00 ⇒ -4(3h + 2p = 9.00) ⇒ <u> -12h - 8p = -36.00</u>
7p = 10.50
p = 1.50
Customer 2: 3h + 2p = 9.00 → 3h + 2(1.50) = 9.00 → 3h + 3.00 = 9.00 → 3h = 6.00 → h = 2.00
Answer: hot dog = $1.50, potato chips = $2.00
