{"id":594,"date":"2025-08-04T10:22:32","date_gmt":"2025-08-04T10:22:32","guid":{"rendered":"https:\/\/giapsgk.com\/chuyen-de\/?page_id=594"},"modified":"2025-08-04T10:22:32","modified_gmt":"2025-08-04T10:22:32","slug":"khai-thac-pha-ban-dau-pha-dao-dong-thoi-diem-trong-bieu-thuc-x-v-a","status":"publish","type":"page","link":"https:\/\/giapsgk.com\/chuyen-de\/dao-dong\/dao-dong-dieu-hoa\/khai-thac-pha-ban-dau-pha-dao-dong-thoi-diem-trong-bieu-thuc-x-v-a\/","title":{"rendered":"Khai th\u00e1c pha ban \u0111\u1ea7u, pha dao \u0111\u1ed9ng, th\u1eddi \u0111i\u1ec3m trong bi\u1ec3u th\u1ee9c x, v, a"},"content":{"rendered":"<p><strong>V\u00ed d\u1ee5 1:<\/strong> Ph\u01b0\u01a1ng tr\u00ecnh dao \u0111\u1ed9ng c\u00f3 d\u1ea1ng x = &#8211; 2sin(\u03c0t &#8211; \u03c0\/4) (trong \u0111\u00f3 x t\u00ednh b\u1eb1ng cm v\u00e0 t t\u00ednh b\u1eb1ng gi\u00e2y). X\u00e1c \u0111\u1ecbnh pha ban \u0111\u1ea7u?<\/p>\n<p>A. \u03c0 rad.<\/p>\n<p>B. 3\u03c0\/4 rad.<\/p>\n<p>C. \u03c0\/4 rad.<\/p>\n<p>D. &#8211; \u03c0\/4 rad.<\/p>\n<p style=\"text-align: center;\"><strong>Gi\u1ea3i<\/strong><\/p>\n<p>x = &#8211; 2sin(\u03c0t &#8211; \u03c0\/4) = 2sin(\u03c0t &#8211; \u03c0\/4 + \u03c0) = 2cos(\u03c0t &#8211; \u03c0\/4 + \u03c0 \u2013 \u03c0\/2) = 2cos(\u03c0t + \u03c0\/4) cm<\/p>\n<p>Ch\u1ecdn C.<\/p>\n<p><strong>V\u00ed d\u1ee5 2:<\/strong> M\u1ed9t v\u1eadt dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh v\u1eadn t\u1ed1c l\u00e0 v = &#8211; 6cos(0,25\u03c0t + \u03c0\/3) (trong \u0111\u00f3 v t\u00ednh b\u1eb1ng cm\/ v\u00e0 t t\u00ednh b\u1eb1ng gi\u00e2y). X\u00e1c \u0111\u1ecbnh pha dao \u0111\u1ed9ng li \u0111\u1ed9 c\u1ee7a v\u1eadt v\u00e0o th\u1eddi \u0111i\u1ec3m t = 4s?<\/p>\n<p>A. 11\u03c0\/6 rad.<\/p>\n<p>B. 5\u03c0\/6 rad.<\/p>\n<p>C. &#8211; \u03c0\/3 rad.<\/p>\n<p>D. &#8211; 5\u03c0\/6 rad.<\/p>\n<p style=\"text-align: center;\"><strong>Gi\u1ea3i<\/strong><\/p>\n<p>x = Acos(\u03c9t + \u03c6) \u2192 v = x\u2018 = &#8211; A\u03c9sin(\u03c9t + \u03c6) = = &#8211; A\u03c9cos(\u03c9t + \u03c6 \u2013 \u03c0\/2) (*)<\/p>\n<p>T\u1eeb d\u1ef1 ki\u1ec7n \u0111\u1ec1 b\u00e0i v\u00e0 (*), ta c\u00f3: \u03c6 \u2013 \u03c0\/2 = \u03c0\/3 \u2192 \u03c6 = 5\u03c0\/6 rad.<\/p>\n<p>V\u1eady pha dao \u0111\u1ed9ng c\u1ee7a v\u1eadt v\u00e0o th\u1eddi \u0111i\u1ec3m 4 s: (\u03c9t + \u03c6) = 20\u03c0t.4 + 5\u03c0\/6 = 11\u03c0\/6 rad<\/p>\n<p>Ch\u1ecdn A.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>V\u00ed d\u1ee5 1: Ph\u01b0\u01a1ng tr\u00ecnh dao \u0111\u1ed9ng c\u00f3 d\u1ea1ng x = &#8211; 2sin(\u03c0t &#8211; \u03c0\/4) (trong \u0111\u00f3 x t\u00ednh b\u1eb1ng cm v\u00e0 t t\u00ednh b\u1eb1ng gi\u00e2y). X\u00e1c \u0111\u1ecbnh pha ban \u0111\u1ea7u? A. \u03c0 rad. B. 3\u03c0\/4 rad. C. \u03c0\/4 rad. D. &#8211; \u03c0\/4 rad. Gi\u1ea3i x = &#8211; 2sin(\u03c0t &#8211; \u03c0\/4) = 2sin(\u03c0t &#8211; \u03c0\/4 &#8230; <a title=\"Khai th\u00e1c pha ban \u0111\u1ea7u, pha dao \u0111\u1ed9ng, th\u1eddi \u0111i\u1ec3m trong bi\u1ec3u th\u1ee9c x, v, a\" class=\"read-more\" href=\"https:\/\/giapsgk.com\/chuyen-de\/dao-dong\/dao-dong-dieu-hoa\/khai-thac-pha-ban-dau-pha-dao-dong-thoi-diem-trong-bieu-thuc-x-v-a\/\" aria-label=\"\u0110\u1ecdc th\u00eam v\u1ec1 Khai th\u00e1c pha ban \u0111\u1ea7u, pha dao \u0111\u1ed9ng, th\u1eddi \u0111i\u1ec3m trong bi\u1ec3u th\u1ee9c x, v, a\">\u0110\u1ecdc ti\u1ebfp<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":580,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-594","page","type-page","status-publish"],"_links":{"self":[{"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/pages\/594","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/comments?post=594"}],"version-history":[{"count":2,"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/pages\/594\/revisions"}],"predecessor-version":[{"id":596,"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/pages\/594\/revisions\/596"}],"up":[{"embeddable":true,"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/pages\/580"}],"wp:attachment":[{"href":"https:\/\/giapsgk.com\/chuyen-de\/wp-json\/wp\/v2\/media?parent=594"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}