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Mathematics 19 Online
OpenStudy (priyar):

Calculus Q..(below)

OpenStudy (priyar):

\[g(x)=\int\limits_{0}^{x} \cos4tdt \] then \[g(x+\pi)\] equals?

OpenStudy (priyar):

[write in terms of g(x) and g(pi)]

OpenStudy (priyar):

running on ups so i will see as much as i can now and the rest as soon as the connection returns...

OpenStudy (priyar):

any idea anyone?

OpenStudy (priyar):

@freckles @ParthKohli @zepdrix

zepdrix (zepdrix):

\[\Large\rm g(\color{orangered}{x})=\int\limits\limits_{0}^{\color{orangered}{x}} \cos4tdt\]So then,\[\Large\rm g(\color{orangered}{x+\pi})=\int\limits\limits_{0}^{\color{orangered}{x+\pi}} \cos4tdt\]

zepdrix (zepdrix):

Do the integration, plug in the new limit

zepdrix (zepdrix):

write in terms of g(x) and g(pi) ? Hmm interesting

OpenStudy (priyar):

@zepdrix ?

zepdrix (zepdrix):

sup? :D

zepdrix (zepdrix):

First get a solution for g(x). Integrate, plug in the stuff.

OpenStudy (priyar):

hey i did that already...

zepdrix (zepdrix):

You did..?

OpenStudy (priyar):

\[g(x)=\frac{ \sin4x }{ 4x }\]

zepdrix (zepdrix):

Woops,\[\large\rm g(\color{orangered}{x})=\frac{\sin4\color{orangered}{x}}{4}\]right? I'm not sure where the bottom x is coming from :D

OpenStudy (priyar):

oh typo

OpenStudy (priyar):

and \[g(x+\pi) =\frac{ \sin(4\pi +4x )}{ 4 }\]

OpenStudy (priyar):

which is..\[g(x+\pi) = \sin4x/4\]

zepdrix (zepdrix):

Pull the 4 out front, it's so ugly down there >.<\[\large\rm g(\color{orangered}{x})=\frac{1}{4}\sin4\color{orangered}{x}\] k looks good D\[\large\rm g(\color{orangered}{x+\pi})=\frac{1}{4}\sin4\color{orangered}{(x+\pi)}\]

zepdrix (zepdrix):

Because adding 4pi just spins us around twice, landing in the same place? Good good good. So we've discovered that g(x+pi) = g(x).

OpenStudy (priyar):

yup!

OpenStudy (priyar):

but the problem is... g(pi)=0

zepdrix (zepdrix):

what? :U

OpenStudy (priyar):

\[g(\pi) = 1/4 (\sin4\pi) =0\] right?

zepdrix (zepdrix):

yes.

OpenStudy (priyar):

yeah so \[g(x+\pi)=g(x) \pm d(\pi)\] right?

OpenStudy (priyar):

thats not d! thats g

zepdrix (zepdrix):

Why would \(\large\rm g(x+\pi)=g(x)+g(\pi)\) ? :o hmmm Oh because g(pi)=0. Ya ya ya I suppose that's a clever observation :) You could include that in your result.

OpenStudy (priyar):

Thanks!

OpenStudy (priyar):

but the problem isit has both options..

OpenStudy (priyar):

both + and - separately...

zepdrix (zepdrix):

\[\large\rm g(x+\pi)=\frac14\sin(4x+4\pi)\]\[\large\rm g(x+\pi)=\frac14\left[\sin4x \cos4\pi+\sin4\pi \cos4x\right]\]\[\large\rm g(x+\pi)=g(x)\cos4\pi+g(\pi) \cos4x\]If you use your angle sum formula for sine, you get some crazy business like this. So maybe they want you to pick the one with +. Sorry I'm not sure :( Weird problem... hmm

OpenStudy (priyar):

well i still think its plus or minus..maybe its a printing mistake..Thanks

zepdrix (zepdrix):

ya plus/minus makes more sense :D

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