Melody

https://www.desmos.com/calculator/e9k8v4rzew

http://web2.0calc.com/questions/random-puzzle-v2

Here are the rest of the interest posts. 

1) Sum of rates questions can be really tricky.  Thanks CPhill

http://web2.0calc.com/questions/lee-can-frame-a-cabin-in-4-days-less-than-ron-when-they-work-together-they-will-do-the-job-in-4-days-how-long-would-each-of-them-take-to#rr2

2) Making mathematical sense of words.  Thanks Chris

http://web2.0calc.com/questions/bobette-is-an-excellent-athlete-in-school-she-competed-in-lacrosse-soccer-softball-and-tennis-she-won-6-more-awards-in-lacrosse-than-in

3) Differentiating Trig - always fun :)     Melody

http://web2.0calc.com/questions/what-is-derivative-of-secx-2

4) Binomials, factorial and gamma functions - Thanks Geno and Alan and Quinn for providing question :)

http://web2.0calc.com/questions/in-a-trail-supposea-lawyer-wants-2-men-and-5-womento-make-up-a-special-panel-so-the-formlar-is-ncr-n-r-n-r-right-so-5c2-5-2-5-2

5) I think the children will like this one - Thanks CPhill, DragonSlayer554 and anon.

http://web2.0calc.com/questions/how-many-licks-does-it-take-to-get-to-the-center-of-a-totsiepop

That is it for tonight.     

                        ♫♪  ♪ ♫                                ♬ ♬ MELODY ♬ ♬                           ♫♪  ♪ ♫ 

http://web2.0calc.com/questions/cphill-s-puzzle-for-the-day

2) What is the number Phi   -   Thanks Geno and Chris

http://web2.0calc.com/questions/what-is-the-number-phi

3) This trigonometry (tides) one took some thought, Chris also gave an approximate answer that was more easily found  -  CPhill and Melody

http://web2.0calc.com/questions/the-captain-of-a-shipping-vessel-must-consider-the-tides-when-entering-a-seaport-high-tide-is-at-5am-at-10-6-meters-and-low-tide-is-at-11am#r1

4) Finding the vertex from a quadratic equations. this is a realyy good one for people to understand.  Thanks Chris.

http://web2.0calc.com/questions/what-is-the-vertex-of-x-2-8x-5

5) A simple question that our budding mathematicians should understand :)  Thanks Chris

http://web2.0calc.com/questions/intermediate-value#r2

6) There is always more to learn.  Thanks Rosala for biginning this thread and thanks to the anon who draw our attention back to it.   

 http://web2.0calc.com/questions/lets-end-the-day-by-learning-something

7) This Physics one looks interesting but I haven't had time to really think about it yet.    Thanks Alan  

 http://web2.0calc.com/questions/motion-in-2-dimension

                        ♫♪  ♪ ♫                                ♬ ♬ MELODY ♬ ♬                           ♫♪  ♪ ♫