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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: TMJ on February 10, 2013, 11:47:24 pm

Title: question?
Post by: TMJ on February 10, 2013, 11:47:24 pm

The depth D meters below sea level of a submarine after time T minutes is given by the trigonometric equation D=4cosT-4 where T greater or equal to 0. When will be the next time the submarine surfaces(D=0) it it was at the surface 3:10pm, initially?

Title: Re: question?
Post by: Mao on February 11, 2013, 01:02:51 am

Assuming you have the question right, the answer is 3:16PM.

Title: Re: question?
Post by: Daenerys Targaryen on February 11, 2013, 04:27:13 pm

Let D=0 and solve for t
having said that the let the first t that makes d=0 be 3:10pm. Then just find the next t intercept and minus the initial t from this; add these many minutes to 3:10pm