sinusoidal function need help!

http://cdn.mathhelpforum.com/images/icons/icon4.png sinusoidal function need help! need this asap for a test and i don't know how to solve it when it doesn't have an x in the equation

problem is : find the a, b, c ,d of y=25sin(1.3pi+0.4pi*t)+28

i know a is 25

d is 28

how to solve b and c?

Re: sinusoidal function need help!

Were you under the impression that this made sense?

It is impossible to tell what "a, b, c, and d" are without knowing what formula you are talking about! How are "a, b, c, and d" defined?