[size=150] Below is a list of very good sites that are free to use. If the tool you need isn't there just yet use Google.I recommend these sites as they offer

[size=150]One of the best![/size]
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Here's one of the first to stop at for PROBLEM SOLVING, SELF TESTS, CALCULATORS AND FOR FORMULAS.
http://www.mathportal.org/ [size=85]<---- highlight and right click goto.[/size]

It is very simply designed with great navigation and excellent very defined search engine. Will fit most needs with all the calculators for maths, and formula you like. The search engine is the most useful tool!
Easy to use for all levels, and on a sliding scale of complexity depending on what you want to achieve. The more complex maths you are looking up, the more that's required to perhaps use the tool you need. ie basic understanding of how to use an online graphing calculator if it's what you want. That shouldn't be out of your reach!
Easy to use input to get output tools- eg, polynomial calculator.. 3 types.. put in your equation and get an answer. It also generates problems! BONUS!
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Thanks

Stu,
Learning E&E

https://www.khanacademy.org/math/trigonometry/conics_precalc/parabolas_precalc/e/parabola_intuition_2

Parabola, focus and directrix graph

I found khanacademy really good. It does suggest a donation but I didn't see any push for it

This page has a parabola, you can change the focus and the directrix and it will change the parabola and the formula accordingly.
or
you can change the focus and the directrix to correspond with the equation given.

I thought it was fun

[size=150] Log calculator.[/size]

Solve any log function calculator. The fun and informative blog is last dated 2008.)
Yes, the calculator even solves x= log ₂₃₁₃166667
To apply a new base just re-enter your base in. (left hand side under the image.)

This is a log calculator. Enjoy.
http://logbase2.blogspot.com.au/2008/08/log-calculator.html
It does not offer an example for the method. Nice to check answers or work though long problems with speed.

tmp_again-506458250.png

Solve any log function, yes even x= log ₁₂₃₄166667

This is easy to do with change of base law
it equals
log ₁₀166667 / log ₁₀1234
= 1.6892

[size=150]Statistics: Comprehensive explanations of statistics and how they are applied from a to z.[/size]


Site layout is a bit mesmerizing with the amount of text on the subject, but you can visualise the titles and subtitles easy enough to read what you want with out fuss and jump to your spot.
The site is a bit of an overload, but if you wanted to verify something about statistics, or learn more about the subject then this would be a good place to do it. "I will for my Engineering."

Link on statistics page. To go to index scroll up and click "Back to the Table of Contents"
http://www.andrews.edu/~calkins/math/edrm611/edrm07.htm#POINTS

Excellent overall but comprehensive for better than average understanding.
Screenshot-1.png
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[size=150]Calculus or Algebra explained: YOUTUBE LINKS TO UMKC LECTURES.[/size]

Stuck on Calculus or Algebra, watch this series of videos from this UMKC professor on youtube.
Calculus: http://www.youtube.com/watch?v=CtRAHmeWSC0 <-- Highlight, right click and select go to.
Algebra: http://www.youtube.com/watch?v=1Amt_-uB9QQ <-- Highlight, right click and select go to.

These UMKC lectures on Calculus have user comments giving 5 out of 5 basically. And for Algebra lessons.
I've watched a number of the Calculus videos and agree. They are very well explained and cover most, if not all of the core information required for understanding the subjects.
Some understanding helpful but not necessary, as it's all there in the set of videos.

[size=150]Nrich: Awesome pictorial based learning site: learn your way through what you want to know easily.[/size]

It is worth a stop for all age groups. There is a few ways to find information on the site. I recommend the search option, or topics list. But you can also click on an appropriate learning level and go to early secondary learning for example. The site has had a lot of effort put into it. So don't let it go to waste. Get what you want to know at your finger tips.

Nrich: http://nrich.maths.org/frontpage <-- highlight and right click, then go to.

This above Nrich site is a part of " uc-rgb.jpg Copyright © 1997 - 2014. University of Cambridge. All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project."


It has a good layout, great search engine and a wide variety of topics all with pictures to help understand your way through the learning.
You'l only find good answers, tools or other useful stuff you might be looking for. Not much missing, if there is try the first link in this post to www.mathportal.org.

[size=150]Tiger Maths: Algebra explained and illustrated. [/size]

The site is simple, well explained and with illustrations. Covering all the key algebra concepts and formula with a plethora of examples answered.
http://www.tiger-algebra.com/

Awesome site for those people learning Algebra.

Bump

[size=150]Pauls online notes[/size]

Great site for revision and learning, with easy navigation. Examples you can understand, solutions, rules, pdf downloadable etc.
A really great site.

http://tutorial.math.lamar.edu/Extras/AlgebraTrigReview/SimpRatExp.aspx <--- highlight right click and goto.

Includes, all calc, 1, 2, 3, trig etc all of what you will need- cheat sheets, common math errors made and more.

Thanks, Stu. I discovered this site some years ago. It's quite excellent. He used to have a more thorough section on Trig as well as a whole section devoted to Linear Algebra, too.
The one on Linear Algebra was FIFTY times better than the class I took in college!! I suppose that the powers-that-be at Lamar University forced him to take these down, but I'm only guessing. Still, it's a good resource.......thanks for posting it to the forum.