Calculus Help!!!?

Question

1. Every sinusoid can be written as y=A cos(Bx+C) for some real numbers A, B, C. True or False? and why?

2. The graph of y=f(x) is a sinusoid with period 45 passing through the point (6,0). Which of the following can be determined from the given information?

I. f(0)
II. f(6)
III. f(96)

A. I only
B. II only
C. I and III only
D. II and III only
E. I, II, and III only

Answer 1

True.A indicates amplitude
B=w=2pi*f and C is the phase angle for x=0
2) y= A cos(Bx+C)

1/T= f and B=2pif so B =2pi/T=0.1396
so
y=Acos(0,1396x+C)
0=A *cos (0.8378+C)
As A can´t be 0 cos(0.8378 +C)= 0 so
0.8378+C=pi/2 so C= 0.7330
y=A cos(0.1396 x+0.7330)

f(6)=0 only.
A is missing