PDA

View Full Version : How to find + c without given information


XTTX
Dec18-08, 03:59 AM
OK, well this is probably a pretty basic problem. I understand all of it except for one part.

1. The problem statement, all variables and given/known data

If F(x)=\int^{x}_{0} sin(t)dt, where x \geq 0, what is the maximum value of F?

2. Relevant equations

F(x)=\int^{x}_{0} sin(t)dt

3. The attempt at a solution

F(x)=\int^{x}_{0} sin(t)dt = -cos(x) + c
max = 1 + c

How do you find c?

If solving with a graphing calculator: y^{}_{1} = Fnint(sin(t),t,0,x) then the answer is 2; I just don't know how the calculator found the shift.

Tedjn
Dec18-08, 04:06 AM
Actually, the C should not be there, because you have a definite integral :smile: That is, your solution F(x) is actually [-cos(x) + C] - [-cos(0) + C], and the C cancels out.

XTTX
Dec18-08, 04:08 AM
Oh wow, I feel really dumb now XD. I guess pulling an all-nighter isn't the best thing for my brain, but thank you for clearing that up.