{"id":1345,"date":"2017-10-29T15:39:51","date_gmt":"2017-10-29T19:39:51","guid":{"rendered":"http:\/\/blog.richmond.edu\/math320\/?p=1345"},"modified":"2017-10-29T15:43:11","modified_gmt":"2017-10-29T19:43:11","slug":"definitions-102617","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/math320\/2017\/10\/29\/definitions-102617\/","title":{"rendered":"Definitions 10\/26\/17"},"content":{"rendered":"<p>The Intermediate Value Theorem:<\/p>\n<p>In the book, we have the formal definition stating: Let f : [a, b] \u2192 R be continuous. If L is a real number satisfying f(a) &lt; L &lt; f(b) or f(a) &gt; L &gt; f(b), then there exists a point c \u2208 (a, b) where f(c) = L.<\/p>\n<p>To prove this theorem, we mainly have three possible approaches:<\/p>\n<ol>\n<li>Using the axiom of completeness.<\/li>\n<li>Using the nested interval property.<\/li>\n<\/ol>\n<p>Details are required in the written homework.<\/p>\n<p>Then, we moved on to chapter 5 where we discussed differentiation. The definition of differentiability is stated as:<\/p>\n<p>Let g : A \u2192 R be a function defined on an interval A. Given c \u2208 A, the derivative of g at c is defined by <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g%27%28c%29+%3D+%5Clim_%7Bx%5Crightarrow+c%7D%5Cfrac%7Bg%28x%29-g%28c%29%7D%7Bx-c%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g&#039;(c) = &#92;lim_{x&#92;rightarrow c}&#92;frac{g(x)-g(c)}{x-c}\" class=\"latex\" \/> provided this\u00a0limit exists. In this case we say g is differentiable at c. If <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g%27&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g&#039;\" class=\"latex\" \/> exists for all points c \u2208 A, we say that g is differentiable on A.<\/p>\n<p>Then, Theorem 5.2.3 states that\u00a0If g : A \u2192 R is differentiable at a point c \u2208 A, then g is continuous at c as well.<\/p>\n<p>To prove this,\u00a0Algebraic Limit Theorem for functional limits allows us to write <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Clim_%7Bx%5Crightarrow+c%7D%28g%28x%29-g%28c%29%29%3D%5Clim_%7Bx%5Crightarrow+c%7D%28%5Cfrac%7Bg%28x%29+-+g%28c%29%7D%7Bx-c%7D%29%28x-c%29+%3D+0&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;lim_{x&#92;rightarrow c}(g(x)-g(c))=&#92;lim_{x&#92;rightarrow c}(&#92;frac{g(x) - g(c)}{x-c})(x-c) = 0\" class=\"latex\" \/>. Therefore, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Clim_%7Bx%5Crightarrow+c%7Dg%28x%29+%3D+g%28c%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;lim_{x&#92;rightarrow c}g(x) = g(c)\" class=\"latex\" \/>.<\/p>\n<p>Algebraic Differentiability Theorem:<\/p>\n<p>Let f and g be functions defined on an interval A, and assume both are differentiable at some point c \u2208 A. Then:<\/p>\n<ol>\n<li><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28f%2Bg%29%27%28c%29+%3D+f%27%28c%29%2Bg%27%28c%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(f+g)&#039;(c) = f&#039;(c)+g&#039;(c)\" class=\"latex\" \/><\/li>\n<li><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28kf%29%27%28c%29+%3D+kf%27%28c%29+%5Cforall+k%5Cin%5Cmathbb%7BR%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(kf)&#039;(c) = kf&#039;(c) &#92;forall k&#92;in&#92;mathbb{R}\" class=\"latex\" \/><\/li>\n<li><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28fg%29%27%28c%29+%3D+f%27%28c%29g%28c%29+%2B+f%28c%29g%27%28c%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(fg)&#039;(c) = f&#039;(c)g(c) + f(c)g&#039;(c)\" class=\"latex\" \/><\/li>\n<li><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28f%2Fg%29%27%28c%29+%3D+%5Cfrac%7Bg%28c%29f%27%28c%29-f%28c%29g%27%28c%29%7D%7B%5Bg%28c%29%5D%5E2%7D%5Ctext%7B%2C+provided+that+%7Dg%28c%29%5Cneq0&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(f\/g)&#039;(c) = &#92;frac{g(c)f&#039;(c)-f(c)g&#039;(c)}{[g(c)]^2}&#92;text{, provided that }g(c)&#92;neq0\" class=\"latex\" \/><\/li>\n<\/ol>\n<p>&nbsp;<\/p>\n<p>Reference:<\/p>\n<p>Abbott, Stephen. \u201cChapter 4 &amp; Chapter 5.\u201d\u00a0<i>Understanding Analysis<\/i>, Springer, 2015.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Intermediate Value Theorem: In the book, we have the formal definition stating: Let f : [a, b] \u2192 R be continuous. If L is a real number satisfying f(a) &lt; L &lt; f(b) or f(a) &gt; L &gt; f(b), then there exists a point c \u2208 (a, b) where f(c) = L. To prove [&hellip;]<\/p>\n","protected":false},"author":3537,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[58823],"tags":[],"class_list":["post-1345","post","type-post","status-publish","format-standard","hentry","category-definitions"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p7L4E1-lH","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts\/1345","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/users\/3537"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/comments?post=1345"}],"version-history":[{"count":0,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts\/1345\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/media?parent=1345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/categories?post=1345"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/tags?post=1345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}