{"id":1552,"date":"2017-11-21T12:21:53","date_gmt":"2017-11-21T17:21:53","guid":{"rendered":"http:\/\/blog.richmond.edu\/math320\/?p=1552"},"modified":"2017-11-26T12:33:49","modified_gmt":"2017-11-26T17:33:49","slug":"weekly-challenge-hw9-2abc","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/math320\/2017\/11\/21\/weekly-challenge-hw9-2abc\/","title":{"rendered":"HW 9: Challenge 2(a,b,c)"},"content":{"rendered":"<p><em>Tongzhou, 11\/21<\/em><\/p>\n<p>(a) Since <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=L%28h%2CP%29%3D%5Csum_%7Bk%3D1%7D%5En+m_k%28x_k-x_%7Bk-1%7D%29%2C&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"L(h,P)=&#92;sum_{k=1}^n m_k(x_k-x_{k-1}),\" class=\"latex\" \/> <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=m_k&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"m_k\" class=\"latex\" \/> needed to be determined firstly.<\/p>\n<p>By definition, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=m_k+%3D%5Cinf%5C%7Bh%28x%29%3A+x+%5Cin+%5Bx_%7Bk-1%7D%2Cx_k%5D%5C%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"m_k =&#92;inf&#92;{h(x): x &#92;in [x_{k-1},x_k]&#92;}\" class=\"latex\" \/>.<\/p>\n<p>Since <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5Bx_%7Bk-1%7D%2Cx_k%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"[x_{k-1},x_k]\" class=\"latex\" \/> is any partition of <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=%5B0%2C1%5D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"[0,1]\" class=\"latex\" \/>, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=m_k+%3D%5Cinf+%5C%7B1%2C2%5C%7D%3D1.&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"m_k =&#92;inf &#92;{1,2&#92;}=1.\" class=\"latex\" \/><\/p>\n<p>Therefore, <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=L%28h%2CP%29+%3D%C2%A0%5Csum_%7Bk%3D1%7D%5En+m_k%28x_k-x_%7Bk-1%7D%29+%3D%5Csum_%7Bk%3D1%7D%5En+1%28x_k-x_%7Bk-1%7D%29%3D1%281-0%29+%3D1&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"L(h,P) =\u00a0&#92;sum_{k=1}^n m_k(x_k-x_{k-1}) =&#92;sum_{k=1}^n 1(x_k-x_{k-1})=1(1-0) =1\" class=\"latex\" \/>.<\/p>\n<p>(b) Sidework: I want to have <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=U%28h%2CP%29+%3C+1%2B+1%2F10&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"U(h,P) &lt; 1+ 1\/10\" class=\"latex\" \/> which means <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=1%28x_k-0%29%2B2%281-x_k%29%3C1%2B1%2F10.&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"1(x_k-0)+2(1-x_k)&lt;1+1\/10.\" class=\"latex\" \/> I want to determine how far <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=x_k&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"x_k\" class=\"latex\" \/> could be away from <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=1&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"1\" class=\"latex\" \/>.<\/p>\n<p>Thus <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=lim_%7Bk+%5Crightarrow+n%7D%28x_k-0%29+%2B+2%281-x_k%29%3C1.1&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"lim_{k &#92;rightarrow n}(x_k-0) + 2(1-x_k)&lt;1.1\" class=\"latex\" \/> so that <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=1-x_k+%3C0.05&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"1-x_k &lt;0.05\" class=\"latex\" \/>.<\/p>\n<p>Now choose <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=P%3D+%5C%7B0%2C0.96%2C1%5C%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"P= &#92;{0,0.96,1&#92;}\" class=\"latex\" \/>. Again I need to determine <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=M_k&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"M_k\" class=\"latex\" \/> before I find <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=U%28h%2CP%29&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"U(h,P)\" class=\"latex\" \/>.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=M_1+%3D+%5Csup%5C%7Bh%280%29%2C+h%280.96%29%5C%7D%3D+1%2C+M_2+%3D%5Csup+%5C%7Bh%280.96%29%2C+h%281%29%5C%7D%3D2&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"M_1 = &#92;sup&#92;{h(0), h(0.96)&#92;}= 1, M_2 =&#92;sup &#92;{h(0.96), h(1)&#92;}=2\" class=\"latex\" \/>.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=U%28h%2CP%29%3D+1%280.96%29%2B2%281-0.96%29+%3D1.04+%3C+1.1&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"U(h,P)= 1(0.96)+2(1-0.96) =1.04 &lt; 1.1\" class=\"latex\" \/><\/p>\n<p>(c) <em>By the intuition of (b).<\/em><\/p>\n<p>Let <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\" \/>, Choose <img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=P_%5Cepsilon+%3D+%5C%7B0%2C+1-%5Cfrac%7B%5Cepsilon%7D%7B2%7D%2C1%5C%7D&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"P_&#92;epsilon = &#92;{0, 1-&#92;frac{&#92;epsilon}{2},1&#92;}\" class=\"latex\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=M_1+%3D+%5Csup+%5C%7Bh%280%29%2Ch%281-%5Cfrac%7B%5Cepsilon%7D%7B2%7D%29%5C%7D%3D%5Csup+%5C%7B1%2C1%5C%7D%3D1%2C+M_2+%3D%5Csup+%5C%7Bh%281-%5Cfrac%7B%5Cepsilon%7D%7B2%7D%29%2Ch%281%29%5C%7D+%3D%5Csup+%5C%7B1%2C2%5C%7D%3D2&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"M_1 = &#92;sup &#92;{h(0),h(1-&#92;frac{&#92;epsilon}{2})&#92;}=&#92;sup &#92;{1,1&#92;}=1, M_2 =&#92;sup &#92;{h(1-&#92;frac{&#92;epsilon}{2}),h(1)&#92;} =&#92;sup &#92;{1,2&#92;}=2\" class=\"latex\" \/>.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/s0.wp.com\/latex.php?latex=U%28h%2CP_%5Cepsilon%29+%3D+1+%281-%5Cfrac%7B%5Cepsilon%7D%7B2%7D%29%2B2+%281-1%2B%5Cfrac%7B%5Cepsilon%7D%7B2%7D%29%3D1%2B%5Cfrac%7B%5Cepsilon%7D%7B2%7D%3C1%2B%5Cepsilon&#038;bg=ffffff&#038;fg=000&#038;s=0&#038;c=20201002\" alt=\"U(h,P_&#92;epsilon) = 1 (1-&#92;frac{&#92;epsilon}{2})+2 (1-1+&#92;frac{&#92;epsilon}{2})=1+&#92;frac{&#92;epsilon}{2}&lt;1+&#92;epsilon\" class=\"latex\" \/>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tongzhou, 11\/21 (a) Since needed to be determined firstly. By definition, . Since is any partition of , Therefore, . (b) Sidework: I want to have which means I want to determine how far could be away from . Thus so that . Now choose . Again I need to determine before I find . [&hellip;]<\/p>\n","protected":false},"author":3535,"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-1552","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-p2","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts\/1552","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\/3535"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/comments?post=1552"}],"version-history":[{"count":0,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/posts\/1552\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/media?parent=1552"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/categories?post=1552"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.richmond.edu\/math320\/wp-json\/wp\/v2\/tags?post=1552"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}