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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: whatever4321 on February 13, 2013, 06:36:04 pm

Title: unit 1 question help?
Post by: whatever4321 on February 13, 2013, 06:36:04 pm: Can someone please help me with this problem? I attatched a picture of the formula.

The question is: Express g as the subject

How do I do this?
Title: Re: unit 1 question help?
Post by: Homer on February 13, 2013, 06:42:46 pm: Is g equal to 4pi^2l\(t^2)

Steps are t divided by 2pi
Square both sides

You get l/g = t^2/4pi^2

G= 4pi^2l\(t^2)
Title: Re: unit 1 question help?
Post by: Bad Student on February 13, 2013, 06:43:12 pm: Quote from: whatever4321 on February 13, 2013, 06:36:04 pm
Can someone please help me with this problem? I attatched a picture of the formula.

The question is: Express g as the subject

How do I do this?

$ \begin{aligned} t &= 2\pi\sqrt{\frac{l}{g}} \\ \frac{t}{2\pi} &= \sqrt{\frac{l}{g}} \\ \left(\frac{t}{2\pi}\right)^2 &= \sqrt{\frac{l}{g}} \\ \frac{t^2}{4\pi^2} &= \frac{l}{g} \\ g &= \frac{l}{\frac{t^2}{4\pi^2}} \\ &= \frac{4\pi^2l}{t^2} \end{aligned} $
Title: Re: unit 1 question help?
Post by: whatever4321 on February 13, 2013, 08:36:06 pm: Thank you so much!
Title: Re: unit 1 question help?
Post by: hongkyho on February 15, 2013, 06:47:13 pm: Quote from: Bad Student on February 13, 2013, 06:43:12 pm
$ \begin{aligned} t &= 2\pi\sqrt{\frac{l}{g}} \\ \frac{t}{2\pi} &= \sqrt{\frac{l}{g}} \\ \left(\frac{t}{2\pi}\right)^2 &= \sqrt{\frac{l}{g}} \\ \frac{t^2}{4\pi^2} &= \frac{l}{g} \\ g &= \frac{l}{\frac{t^2}{4\pi^2}} \\ &= \frac{4\pi^2l}{t^2} \end{aligned} $

Not wanting to nitpick, but just in case the third step should be l/g on the right side, not sqrt(l/g), since you should have squared both sides in this step.