{"id":1215,"date":"2017-10-22T19:17:52","date_gmt":"2017-10-22T23:17:52","guid":{"rendered":"http:\/\/blog.richmond.edu\/math320\/?p=1215"},"modified":"2017-10-22T22:13:07","modified_gmt":"2017-10-23T02:13:07","slug":"hw6-challenge-1","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/math320\/2017\/10\/22\/hw6-challenge-1\/","title":{"rendered":"HW6: Challenge 1"},"content":{"rendered":"<p>Assume that <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g\" class=\"latex\" \/> is defined on an open interval <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,c)\" class=\"latex\" \/> and it is known to be uniformly continuous on <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cb%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,b]\" class=\"latex\" \/> and <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Bb%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"[b,c)\" class=\"latex\" \/> where <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=a%3Cb%3Cc&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"a&lt;b&lt;c\" class=\"latex\" \/>. Prove that <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g\" class=\"latex\" \/> is uniformly continuous on <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,c)\" class=\"latex\" \/>.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Assume <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g\" class=\"latex\" \/> is defined on an open interval <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,c)\" class=\"latex\" \/>. Suppose <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g\" class=\"latex\" \/> is uniformly continuous on <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cb%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,b]\" class=\"latex\" \/> and <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Bb%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"[b,c)\" class=\"latex\" \/> with <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=a%3Cb%3Cc&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"a&lt;b&lt;c\" class=\"latex\" \/>.<\/p>\n<p>Suppose <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=x%5Cin+%28a%2Cb%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"x&#92;in (a,b]\" class=\"latex\" \/>. Since g is uniformly continuous on <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cb%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,b]\" class=\"latex\" \/>, we know that for any <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cepsilon%3E0&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;epsilon&gt;0\" class=\"latex\" \/>, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cexists%5Cdelta_1%3E0&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;exists&#92;delta_1&gt;0\" class=\"latex\" \/> s.t for <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=x%2Cb%5Cin%28a%2Cb%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"x,b&#92;in(a,b]\" class=\"latex\" \/>, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+x-b%5Cmid%3C%5Cdelta_1&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid x-b&#92;mid&lt;&#92;delta_1\" class=\"latex\" \/> implies <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+g%28x%29-g%28b%29%5Cmid%3C%5Cfrac%7B%5Cepsilon%7D%7B2%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid g(x)-g(b)&#92;mid&lt;&#92;frac{&#92;epsilon}{2}\" class=\"latex\" \/>.<\/p>\n<p>Similarly suppose <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=y%5Cin+%5Bb%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"y&#92;in [b,c)\" class=\"latex\" \/>. Since <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g\" class=\"latex\" \/> is uniformly continuous on <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Bb%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"[b,c)\" class=\"latex\" \/>, we know that for any <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cepsilon%3E0&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;epsilon&gt;0\" class=\"latex\" \/>, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cexists%5Cdelta_2%3E0&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;exists&#92;delta_2&gt;0\" class=\"latex\" \/> s.t. for <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=y%2Cb%5Cin+%5Bb%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"y,b&#92;in [b,c)\" class=\"latex\" \/>, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+y-b%5Cmid%3C%5Cdelta_2&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid y-b&#92;mid&lt;&#92;delta_2\" class=\"latex\" \/> implies <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+g%28y%29-g%28b%29%5Cmid%3C%5Cfrac%7B%5Cepsilon%7D%7B2%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid g(y)-g(b)&#92;mid&lt;&#92;frac{&#92;epsilon}{2}\" class=\"latex\" \/>.<\/p>\n<p>Choose <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cdelta%3D%5Cmin%5C%7B%5Cdelta_1%2C%5Cdelta_2%5C%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;delta=&#92;min&#92;{&#92;delta_1,&#92;delta_2&#92;}\" class=\"latex\" \/> so that <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+x-y%5Cmid%3C%5Cdelta&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid x-y&#92;mid&lt;&#92;delta\" class=\"latex\" \/> implies <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+x-b%5Cmid%3C%5Cdelta&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid x-b&#92;mid&lt;&#92;delta\" class=\"latex\" \/> and <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+y-b%5Cmid%3C%5Cdelta&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid y-b&#92;mid&lt;&#92;delta\" class=\"latex\" \/>. Thus, applying the triangle inequality, for all <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=x%2Cy%5Cin+%28a%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"x,y&#92;in (a,c)\" class=\"latex\" \/>, if <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+x-y%5Cmid%3C%5Cdelta&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid x-y&#92;mid&lt;&#92;delta\" class=\"latex\" \/>, it follows that<\/p>\n<p>$<img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Cmid+g%28x%29-g%28y%29%5Cmid%3D%5Cmid+g%28x%29-g%28b%29%2Bg%28b%29-g%28y%29%5Cmid%5Cleq%5Cmid+g%28x%29-g%28b%29%5Cmid%2B%5Cmid+g%28y%29-g%28b%29%5Cmid%3C%5Cfrac%7B%5Cepsilon%7D%7B2%7D%2B%5Cfrac%7B%5Cepsilon%7D%7B2%7D%3D%5Cepsilon&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"&#92;mid g(x)-g(y)&#92;mid=&#92;mid g(x)-g(b)+g(b)-g(y)&#92;mid&#92;leq&#92;mid g(x)-g(b)&#92;mid+&#92;mid g(y)-g(b)&#92;mid&lt;&#92;frac{&#92;epsilon}{2}+&#92;frac{&#92;epsilon}{2}=&#92;epsilon\" class=\"latex\" \/>$<\/p>\n<p>Thus, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=g&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"g\" class=\"latex\" \/> is uniformly continuous on <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%28a%2Cc%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"(a,c)\" class=\"latex\" \/> by definition.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Assume that is defined on an open interval and it is known to be uniformly continuous on and where . Prove that is uniformly continuous on . &nbsp; &nbsp; Assume is defined on an open interval . Suppose is uniformly continuous on and with . Suppose . Since g is uniformly continuous on , we [&hellip;]<\/p>\n","protected":false},"author":3526,"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":[58827],"tags":[],"class_list":["post-1215","post","type-post","status-publish","format-standard","hentry","category-challenge-solutions"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p7L4E1-jB","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts\/1215","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\/3526"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/comments?post=1215"}],"version-history":[{"count":0,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts\/1215\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/media?parent=1215"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/categories?post=1215"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/tags?post=1215"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}