Approximation sin(x) taylor Series and Accuracy

engboysclub
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Homework Statement



One uses the approximation sin(x) = x to calculate the oscillation period of a simple gravity pendulum. Which is the maximal angle of deflection (in degree) such that this approximation is accurate to a) 10%, b) 1%, c) 0.1%. You can estimate the accuracy by using the next nonvanishing term of the Taylor series

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The Attempt at a Solution



I'm not sure how to begin.
 
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by using the next nonvanishing term of the Taylor series
You could determine this term to begin.

Afterwards: How do sin(x) and x differ if the approximation is accurate to 10%?
 
I'm not really sure - I know what Taylor series is - Graphically and what it does but I don't know how to implement it or work it out.
 
How do i determine the term ?

How do I calculate the accuracy ?
 
Look in your script/book/wikipedia for the taylor series. You cannot solve the problem without any knowledge about taylor series.

How do I calculate the accuracy ?
If the real value is 0.5 and the approximation is 0.45 (arbitrary numbers), what is the relative deviation?
 
engboysclub said:
I'm not really sure - I know what Taylor series is - Graphically and what it does but I don't know how to implement it or work it out.

The thing to do is just to START: write down the Taylor expansion for sin(x). Stop agonizing over it, and just use what you have been taught; that will get you part way towards the solution. Then, if you are stuck at a later stage, you can ask a more pointed and more meaningful question.

RGV
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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