Add the following to the document head:

• Set the character encoding of the file to utf-8.
• Add the following search keywords: math, Euler, pi, and geometry.
• Set the title of the document to Leonhard Euler (1707-1783).
• Link the document to the ms_base.css and ms_layout.cssstyle sheet files.

Add a header, article, aside, nav, and footer element to the document body.

Within the body header, insert an inline image for the ms_logo.png file with the alternate text Math Strings.

Go to the ms_pages.txt file and copy the text of the main article (located in the first section of the file), including the title. Then, go to the ms_euler.html file and paste the copied text into the article element.

Within the article element, make the following markup changes:

• Mark the text Leonhard Euler (1707-1783) as an h1 heading.
• Mark the three paragraphs of the article content using the pelement.
• In the first paragraph, mark the names Leonhard Euler and Jean Bernoulli as strong text. Mark the phrase 800 different books and papers as emphasized text.
• In the second paragraph mark the works Introductio in analysin infinitorum (1748) and Lettres une princesse dAllemagne (1768-1772) as citations. Insert the character using the character reference à;.
• In the third paragraph, mark the mathematical symbols e and using the var (variable) element. Insert the character by replacing [pi] with the πcharacter reference.

Return to the ms_pages.txt and copy the text of the second section containing information about Eulers Equation, the most beautiful equation in math. Then, go to the ms_euler.html file and paste the copied text into the aside element.

Within the aside element, add the following markup:

• Mark the title The Most Beautiful Equation in Math? as an h1heading.
• Mark the two equations in the pasted text using the codeelement. Mark the three other text groups as paragraphs.
• Throughout the text of the aside element, mark x, I, e, xi, and pi using the var element, replacing [pi] from the pasted text with the character reference π.
• Use the sup element in the following equations to mark xiand i as superscripts:
  • cos(x) + isin(x) = e^xi
  • eⁱ + 1 = 0
• Mark the text The Mathematical Intelligencer as a citation.

Return to the ms_pages.txt file and copy the text of the third section listing more ways to learn about Euler. Then, go to the ms_euler.htmlfile and paste the copied text into the nav element.

Within the nav element, add the following markup:

• Mark the title Learn more about Euler as an h1 heading.
• Mark the four Euler websites as an unordered list.
• Change the text of the Euler websites to hypertext links pointing to the following URLs:
  • Euler at Wikipedia linked to http://en.wikipedia.org/wiki/Leonhard_Euler
  • The Euler Archive linked to http://eulerarchive.maa.org/
  • Euler at Biography.com linked to http://www.biography.com/people/leonhard-euler-21342391
  • Euler at Famous Scientists linked to http://www.famousscientists.org/leonhard-euler

Within the footer element, insert the text Math Strings: A Site for Educators and Researchers.