20181215, 02:36  #122 
May 2011
Orange Park, FL
3·13·23 Posts 
Rewrite as \[\dfrac{1}{2}x^{\frac{1}{2}}\]
(I'm not very fluent with this $$ math coding so please excuse). Now just use the power rule. minus 1/2 times 1/2 and subtract one from the power of x. Result is 1/(4 x^(3/2)) Last fiddled with by LaurV on 20181215 at 04:16 Reason: fixed the missing parenthesis in the formula  now it shows right :) 
20181215, 02:38  #123 
May 2011
Orange Park, FL
1601_{8} Posts 
Where can I read about how to use this $$ math formatting?

20181215, 02:48  #124 
veganjoy
"Joey"
Nov 2015
Middle of Nowhere,AR
2^{2}·3·37 Posts 
It’s called Latex! \(\LaTeX\)
Most of the time you can just put plain text formatting in and it’ll look better. But you have to use a bit of Latex code for fractions, roots, and other symbols. Google should be able to help you out, and there are online editors with buttons that insert code for you 
20181215, 04:22  #125 
Romulan Interpreter
"name field"
Jun 2011
Thailand
2645_{16} Posts 
You actually got it right, except that a bracket was missing. I fixed it for you. Also, I used \frac instead of \dfrac to let \Latex control the size of indexes and powers.
A very good place to start is to bookmark few lists like this one. You don't need to learn the algorithms how to construct such symbols, just to use what is constructed already, and you also don't need to learn them by heart, you will remember them as you use them day by day, and when you need new stuff, consult the list. Some may not work, as we use here a subset of Latex, called Mathjax. Some standard symbols are missing, but some other new are introduced. You can also create your own. Also, here on the forum you don't need to use the double dollar, we have \( and respectively \[ to put formulas in text and respectively on separate line (also mathjax feature). If you still insist in having a WYSIWYG TeX editor, you can look on the web. Most of them cost money, but few are free and moderate powerful. They can let you edit equations like word, etc, and generate LaTeX code that you can paste on the forum. If you use mac, then Compositor is a very good tool. Trivia: We remember in the nineties we were programming fractals and chess games in latex, hehe... like an "escape from reality" mechanism... (we were "forced" by our uni to type shitty books and articles of/for our professors  not all of them popular with students, as we were thinking at that age...). Last fiddled with by LaurV on 20181215 at 04:39 
20181215, 09:37  #126  
Dec 2012
The Netherlands
3327_{8} Posts 
Quote:
You accidentally differentiated the outside and then the inside instead of differentiating the outside and then multiplying by the derivative of the inside! 

20181215, 13:25  #127 
Feb 2017
Nowhere
2×2,503 Posts 
The BB Code page in the FAQ. Just click on the highlighted code, and you'll see what it does. In my experience, tex gives the nicestlooking displays.

20181215, 13:58  #128  
May 2011
Orange Park, FL
897_{10} Posts 
Quote:


20181215, 14:56  #129  
veganjoy
"Joey"
Nov 2015
Middle of Nowhere,AR
2^{2}×3×37 Posts 
Quote:
Quote:
I’ll finish it up the original way, since I see now what the more intelligent way looks like... So on the step where I messed up the chain rule, it should really be:\[1(2\sqrt{x})^{2}*(2*\frac{1}{2}*x^{1/2})\]Which really looks like:\[\dfrac{1}{(2\sqrt{x})^{2}}*\dfrac{1}{\sqrt{x}}\]\[\dfrac{1}{4x}*\dfrac{1}{\sqrt{x}}\]\[\dfrac{1}{4x^{3/2}}\]Ok, that seems much better 

20181219, 22:27  #130 
veganjoy
"Joey"
Nov 2015
Middle of Nowhere,AR
2^{2}×3×37 Posts 
I wrote down some of the practice problems from calculus, so I worked them out on paper and took a picture to make sure I’m doing them correctly.
Thanks for the help! Last fiddled with by jvang on 20181219 at 22:31 Reason: typing is hard 
20181220, 08:35  #131 
Romulan Interpreter
"name field"
Jun 2011
Thailand
97·101 Posts 
Well, for the physics problem you won't really need to know integrals/antiderivatives, you can easily use the kinematic formula, \(x=x_0+v_0\cdot t+\frac12\cdot a\cdot t^2\), the first two are zero because it is free fall, the third gives you the space traveled, where acceleration is g. So, yes, \(\frac{3^2\cdot 9.81}2=44.145\) meters.
(Actually, now you just got an idea where the kinematics formulas come from, if you didn't know before  plenty of guys asking on the web where the 1/2 in front of acceleration comes from ). Last fiddled with by LaurV on 20181220 at 08:42 
20181220, 09:11  #132  
Dec 2012
The Netherlands
17×103 Posts 
Quote:
\[ \lim_{x\rightarrow 0}\frac{\sin(2x)}{3x}=\lim_{x\rightarrow 0}\frac{2}{3}\cdot\frac{\sin(2x)}{2x}=\ldots \] 3. I would write \( \frac{d}{dx} \sin(x^21)=\ldots \) instead of just \( \sin(x^21)=\ldots \), otherwise you risk confusing the grader! The same goes for questions 4, 6 & 7. 4. You have made a small mistake in this one: \((2x1)^2=4x^24x+1\). 7. Here, too: \(\frac{d}{dx}(5\sin(2x))=2\cos(2x)\). 

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