- #1
lostcompass
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Homework Statement
The period of f is 5. If f(1)=4, f(2)=5, and f(4)=-2, the value of f(7) is:
Homework Equations
The standard format for trig functions is A[tex]\sin[/tex]B(x-C)+D
A is the amplitude, [tex]\frac{2\pi}{B}[/tex] is the period (for sin or cos functions), C is the phase, and D is the vertical displacement.
The Attempt at a Solution
Finding the period of a function when you have the equation is easy, but doing the opposite seems to be impossible. The only way I'm going to figure out the value of f(7) is if I figure out the equation first. Presumably the function is a trig function. If it's a sin function, then the equation must be A[tex]\sin\frac{2\pi}{5}[/tex](x-C)+D, in order for the period to be 5.
Beyond that, I haven't been able to figure out what I should do, because there doesn't seem to be any real pattern to the y values, and my textbook only shows how to find the period from the equation, not how to find values when given vague information. Could someone point me in the right direction?