All Answers 358110 Answers

ya , i understand physics , its easy !

i dont know who has asked this question but its my duty to give the answers i know so 2 + 2 is 4 ! 

8.5

an education

Thanks CPhill!

@@ End of Day Wrap - Friday30/5/14   Sydney, Australia   Time 20:40 pm 

hi everyone,

Our great answers were today provided by chilledz3non, Kitty<3, CPhill, Rom, Alan, Heureka, Reinout-g, Bertie, GoldenLeaf, Themightyalgol and all-them-marvel-feels.  Thank you all.

Themightyalgor joined up yesterday (maybe today) We welcome you to web2.0calc forum and we hope that you find this site helpful and fun!

-----------------------------------------

Here are some posts that some people may find interesting.

(I've included no comic ones today - that's a little sad)

Manipulating logs always causes problems for people (Thanks for the demo Alan)

it also logs me out after replying to a few posts (of my own) when i log back in it kicks me off to post again. As well it logs out after a delay of inactivity. Very annoying and useless function imo. Much improvement with maths fucntionallity etc. 

That is fine. I guess, with regards to integration what is some newb common errors seen, that will be difficult. To answer my own question I would say, identifying the difference between taking the integral of something and taking the derivative of inside the brackets (following rules) would be hard, also knowing the difference between using and not uing x^n+1/n+1. ie not if multiplied or divided. Thanks

Yes, I found the maths and image entering easier for sure. I found some recent post of mine in watch list. But generally the click on your name, find you post and inbox has negatively changed. Finding your recent post is not so easy when you go to recent posts form user, they are all blured into one, and long winded with the "replies from ppl etc, and some are not accessible (i think the most recent.)

$${f}{\left({\mathtt{x}}\right)} = {\mathtt{x}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{x}}\right)}{\mathtt{\,-\,}}{\frac{{\mathtt{1}}}{{\mathtt{x}}}}$$

Thanks wil lget back to physics next week readying for the exam then.

I don't recognise your calculation as Newton-Raphson. Where does that ln come from ?

If f(x)=x.cos(x)-1/x, then f '(x)=cos(x)-x.sin(x)+1/(x^2), (angles in radians).

Then x(n+1)=x(n)-f(x(n))/f '(x(n)).

There is, I vaguely remember, an algebraic method similar to that for calculating square roots and it's also possible to use the Newton-Raphson method, (though you would need to be good at arithmetic, hardly the sort of calculation you would attempt without a calculator).

If the number is close to some convenient cube, it's possible to make use of the binomial expansion. For example.

$$\begin{array}{lcl}
\sqrt[3]{1005}&=&(1000+5)^{1/3}\\
&=&1000^{1/3}(1+0.005)^{1/3}\\
&=&10(1+(1/3)0.005+(1/3)(-2/3)0.005^{2}/2!+\dots)\\
&=&10(1+0.0016667-0.0000028+\dots)\\
&\approx&10.016639
\end{array}$$

That's easily done on paper and is correct to 6dp.

Answer given is 5.166r solved to the 1st degree of accuracy.

I put in the missing bracket but it still is wrong.

Here's the result as calculated to 50 decimal places by Mathcad's symbolic maths system:

Looks like the local calculator is accurate up to about 11 decimal places.

NB Looks like the image above has cut off the "i" in the decimal answer! 

Rom has assumed compound interest , compounding yearly at 2.3% per annum

BUT really these are just very sensible assumptions on his part.

--------------------------------------------------------------------------

It depends on whether it is compound interest or simple interest.

and

is it 2.3% per annum or per some other time period.

and

If it is compound interest, how often is it compounding.

assuming interest accrues annually you have

$$FV=PV(1+rate)^T$$

$$FV=9600(1.023)^{14}$$

$${\mathtt{9\,600}}{\mathtt{\,\times\,}}{\left({\mathtt{1.023}}\right)}^{{\mathtt{14}}} = {\mathtt{13\,198.668\: \!008\: \!406\: \!117\: \!257\: \!2}}$$

so you would end up with $13,198.67 after 14 yrs.

There is no answer,    $$x^2+6x$$   cannot be simplified.

$${\frac{{\sqrt[{{\mathtt{{\mathtt{3}}}}}]{{\mathtt{9\,764.822\: \!108}}}}{\mathtt{\,\times\,}}{\mathtt{53}}}{{\mathtt{7}}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{14}}}^{{\mathtt{7}}}{\mathtt{\,-\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{75}}^\circ\right)} = {\mathtt{105\,413\,665.573\: \!754\: \!867\: \!608\: \!094\: \!8}}$$