Answer:
Answer is A.
Step-by-step explanation:
For the equation: 35cos(pi/6(m+3)+55)
Simplify it by multiplying pi/6 in the bracket values:
[tex]=35cos(\frac{m.pi}{6}+\frac{3.pi}{6}+55) \\=35cos(\frac{m.pi}{6}+55+\frac{pi}{2})[/tex]
Now suppose x = m.pi/6+55, while pi/2 = 90⁰
As per law cos(x+90⁰)=-sin(x)
so,
cos((m.pi/6)+55+90⁰=-sin((m.pi/6)+55)
Hence answer will be
[tex]=-35sin(\frac{m.pi}{6}+55)[/tex]
.
The law cos(x+90⁰)=-sin(x) can be proved by putting y=90⁰ in the following formula,
cos(x+y)=cos(x).cos(y)-sin(x).sin(y)
