{"id":20,"date":"2016-01-28T22:06:50","date_gmt":"2016-01-29T05:06:50","guid":{"rendered":"https:\/\/blogs.ubc.ca\/conwaychen\/?p=20"},"modified":"2016-01-28T22:06:50","modified_gmt":"2016-01-29T05:06:50","slug":"tips-of-u-substitution","status":"publish","type":"post","link":"https:\/\/blogs.ubc.ca\/conwaychen\/2016\/01\/28\/tips-of-u-substitution\/","title":{"rendered":"Tips of U-substitution"},"content":{"rendered":"<p>When we are solving for more complicated integrals, we will use U-substitution to make our life easier. However, sometimes choosing the right &#8220;u&#8221; may affect our process a lot. \u00a0Here are some tips to help people choose the &#8220;u&#8221; easier:<\/p>\n<p>First of all, choose the function that is not in its simplest form. For example, when we are evaluating the integral of xcos(x^2), we should choose x^2 as our &#8220;u&#8221; because du=2xdx. When we do the u-substitution, we have to represent the integral with respect to u, which means dx at this point, will be equal to du\/2x. Then, with one x in each of the denominator and the numerator, we are able to cancel it. Thus, the integral will look much more simple.<\/p>\n<p>Secondly, when there is a rational function, \u00a0we will try to get rid of the function at the numerator. So in this case, we will choose the function at the denominator as our &#8220;u&#8221;. For example, if we want to evaluate the integral of x\/((x^2) + 3), we will choose u=(x^2) + 3 so that later on the x in the denominator and the numerator will cancel out each other.<\/p>\n<p>Lastly, when we are evaluating the integrals of the product of trigonometric functions, try to think of their derivatives then\u00a0decide which should be represented as &#8220;u&#8221;. For example, if we are to evaluate the integral of tan^3(x)sec^2(x), we should choose u=tan(x) because we know that the derivative of tan(x) is sec^2(x). Then the sec^2(x) will cancel out each other eventually.<\/p>\n<h1 id=\"firstHeading\" class=\"firstHeading\" lang=\"en\"><\/h1>\n","protected":false},"excerpt":{"rendered":"<p>When we are solving for more complicated integrals, we will use U-substitution to make our life easier. However, sometimes choosing the right &#8220;u&#8221; may affect our process a lot. \u00a0Here are some tips to help people choose the &#8220;u&#8221; easier: First of all, choose the function that is not in its simplest form. For example, [&hellip;]<\/p>\n","protected":false},"author":35353,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-20","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/posts\/20","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/users\/35353"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/comments?post=20"}],"version-history":[{"count":1,"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/posts\/20\/revisions"}],"predecessor-version":[{"id":21,"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/posts\/20\/revisions\/21"}],"wp:attachment":[{"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/media?parent=20"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/categories?post=20"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/conwaychen\/wp-json\/wp\/v2\/tags?post=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}