Association and TemplateApply problem in associations section of The Wolfram Language:Fast introduction to programmers

I am going over The Wolfram Language:Fast introduction to programmers. In the associations section, following question and answer is given

Which of the following applies a template to make a string with appetizer and dessert from the association

 meal=<|"appetizer" →"nachos", "salad" → "spinach", "dessert" → "chocolate"|>
 TemplateApply["The appetizer is `appetizer` and the dessert is `dessert`.", meal]

But in my mathematica notebook, I am getting errors from the above two lines of code.

Incompatible elements in Join …. cannot be joined.

But according to web site, this is correct answer. Where is my mistake?

Problem 8.8(a) Apostol introduction to analytic number theory

I am self studying analytic number theory from Tom Apostol and couldn’t solve this particular question which is 8(a) of chapter 8 on page 175.

It’s image:enter image description here

Attempt: I thought of proving that for every $a_i$ that satisfies $aequiv a_{i} (mod k_i) $ will satisfy $a_{i} equiv 1 (mod k_j) $ .

But I couldn’t. Also, I realized that this will not prove existence of $a_i$ .

So, I am struck on this problem and need your help.


Which textbook provides the best introduction to Bitcoin?


The best one is Bitcoin and Cryptocurrency Technologies by Narayanan & Bonneau et al.
You can get a draft version for free from Arvind Narayanan’s blog.

The one by Andreas M. Antonopoulos, Mastering Bitcoin is good too.

Roger Wattenhofer & Christian Decker et al also wrote a nice one called “The Science of the Blockchain” about blockchains in general.

My Introduction

  • Big hello to admin and to all members of this forum. I am Alan, i from asia and We have a team working as freelancer on designing websites, software design and development.
    We have created and worked on 100+ projects websites, plugins, templates and software. I joined this forum because I plan to share with you my knowledge and projects.
    Looking forward to participate and interact with all you guys.
    I wish all luck and success to everyone.

ux designer – Web/Mobile application introduction page practices

I have a web site, but the first time a user navigates there, I wish to do a small introduction of
the exact purpose of the web site, ie. explain what we can do with it and how etc…

I have seen such on Pinterest by example, the first time you navigate the gives a short introduction like this:

enter image description here

So, I have a few questions:

  • Is it good practices ? or not ?
  • Are there other approaches?
  • Does having animation is interesting ? do we need them or not and why?
  • Is it better to use “real photo” or “drawing”… I have the feeling that photos are more concrete.
  • Does this kind of specific page have a specific name? It is not a landing page, right?
  • Are there other examples and/or alternatives.
  • How can we have such kind of introduction on mobile?
  • Should I directly propose a registration or propose to continue on the web site?
    What is the best for engagement & retention?

Any additional information is welcome.


Hello, hope everyone is good

My name is Melisa Assunta from USA and i am working as business development manager . I recently visit this plateform and it looks very professional. I hope everyone is having great time here