Math Is Fun Forum

Johnathan1

Member

Registered: 2006-06-10

Posts: 7

A problem.

Hey. Hope everyones well. First post on this forum !!!! I had this question regarding an equation, its about max/min point and re-arraning.

Heres the equation:

The current in an A.C. circuit at any time "t" seconds is given by:

        i = 80sin (100*pi*t + 0.47)

1) The time when the current is a minimum

2)The times when i = 0.

Johnathan1

Member

Registered: 2006-06-10

Posts: 7

Re: A problem.

Hey, can anybody not help on this?

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: A problem.

2) substitute with 0 and solve for t.

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IPBLE:  Increasing Performance By Lowering Expectations.

Johnathan1

Member

Registered: 2006-06-10

Posts: 7

Re: A problem.

hmmm but krassi, thats the problem. its asking for times! if i substitute with 0. it will only give me one time.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 46,224

Re: A problem.

Find di/dt. Put di/dt=0. Substitute the values in d²i/dt². If d²i/dt² positive, i is minimum.

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