{"id":4394,"date":"2022-06-13T06:51:45","date_gmt":"2022-06-13T06:51:45","guid":{"rendered":"https:\/\/mdr.foobrdigital.com\/?p=4394"},"modified":"2022-06-13T06:51:45","modified_gmt":"2022-06-13T06:51:45","slug":"derivation-of-trapezoidal-rule-formula","status":"publish","type":"post","link":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/2022\/06\/13\/derivation-of-trapezoidal-rule-formula\/","title":{"rendered":"Derivation of Trapezoidal Rule Formula"},"content":{"rendered":"\n<p>We can calculate the value of a definite integral by using trapezoids to divide the area under the curve for the given function.<\/p>\n\n\n\n<p><strong>Trapezoidal Rule Statement:<\/strong>&nbsp;Let f(x) be a continuous function on the interval (a, b). Now divide the intervals (a, b) into n equal sub-intervals with each of width,<\/p>\n\n\n\n<p><strong>\u0394x = (b &#8211; a)\/n<\/strong>, such that a = x<sub>0<\/sub>&nbsp;&lt; x<sub>1&nbsp;<\/sub>&lt; x<sub>2&nbsp;<\/sub>&lt; x<sub>3&nbsp;<\/sub>&lt;\u2026..&lt; x<sub>n<\/sub>&nbsp;= b<\/p>\n\n\n\n<p>Then the Trapezoidal Rule formula for area approximating the definite integral&nbsp;<sup>b<\/sup>\u222b<sub>a<\/sub>f(x)dx is given by:<\/p>\n\n\n\n<p><sup>b<\/sup>\u222b<sub>a<\/sub>f(x) dx \u2248 T<sub>n<\/sub>&nbsp;= \u25b3x\/2 [f(x<sub>0<\/sub>) + 2f(x<sub>1<\/sub>) + 2f(x<sub>2<\/sub>) +\u2026.2f(x<sub>n-1<\/sub>) + f(x<sub>n<\/sub>)]<\/p>\n\n\n\n<p>where, x<sub>i<\/sub>&nbsp;= a + i\u25b3x<\/p>\n\n\n\n<p>If n \u2192 \u221e, R.H.S of the expression approaches the definite integral&nbsp;<sup>b<\/sup>\u222b<sub>a<\/sub>&nbsp;f(x)dx<\/p>\n\n\n\n<p><strong>Proof:<\/strong><\/p>\n\n\n\n<p>To prove the trapezoidal rule, consider a curve as shown in the figure above and divide the area under that curve into trapezoids. We see that the first trapezoid has a height \u0394x and parallel bases of length y<sub>0<\/sub>&nbsp;or f(x<sub>0<\/sub>) and y<sub>1<\/sub>&nbsp;or f<sub>1<\/sub>. Thus, the area of the first trapezoid in the above figure can be given as,<\/p>\n\n\n\n<p>(1\/2) \u0394x [f(x<sub>0<\/sub>) + f(x<sub>1<\/sub>)]<\/p>\n\n\n\n<p>The areas of the remaining trapezoids are (1\/2)\u0394x [f(x<sub>1<\/sub>)&nbsp;+ f(x<sub>2<\/sub>)], (1\/2)\u0394x [f(x<sub>2<\/sub>) + f(x<sub>3<\/sub>)], and so on.<\/p>\n\n\n\n<p>Consequently,<\/p>\n\n\n\n<p>\u222b<sup>b<\/sup><sub>a&nbsp;<\/sub>f(x) dx \u2248 (1\/2)\u0394x (f(x<sub>0<\/sub>)+f(x<sub>1<\/sub>) ) + (1\/2)\u0394x (f(x<sub>1<\/sub>)+f(x<sub>2<\/sub>) ) + (1\/2)\u0394x (f(x<sub>2<\/sub>)+f(x<sub>3<\/sub>) ) + \u2026 + (1\/2)\u0394x (f(<sub>n-1<\/sub>) + f(x<sub>n<\/sub>) )<\/p>\n\n\n\n<p>After taking out a common factor of (1\/2)\u0394x and combining like terms, we have,<\/p>\n\n\n\n<p>\u222b<sup>b<\/sup><sub>a&nbsp;<\/sub>f(x) dx\u2248 (\u0394x\/2) (f(x<sub>0<\/sub>)+2 f(x<sub>1<\/sub>)+2 f(x<sub>2<\/sub>)+2 f(x<sub>3<\/sub>)+ &#8230; +2f(<sub>n-1<\/sub>) + f(x<sub>n<\/sub>) )<\/p>\n","protected":false},"excerpt":{"rendered":"<p>We can calculate the value of a definite integral by using trapezoids to divide the area under the curve for the given function. Trapezoidal Rule Statement:&nbsp;Let f(x) be a continuous function on the interval (a, b). Now divide the intervals (a, b) into n equal sub-intervals with each of width, \u0394x = (b &#8211; a)\/n, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[874],"tags":[],"_links":{"self":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/4394"}],"collection":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=4394"}],"version-history":[{"count":0,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/4394\/revisions"}],"wp:attachment":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=4394"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=4394"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=4394"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}