{"id":8079,"date":"2021-11-13T21:28:50","date_gmt":"2021-11-13T15:58:50","guid":{"rendered":"https:\/\/mathemerize.com\/?p=8079"},"modified":"2021-11-14T00:56:33","modified_gmt":"2021-11-13T19:26:33","slug":"find-the-equations-of-the-tangent-and-the-normal-at-the-point-t-on-the-curve-x-a-sin3-t-y-b-cos3-t","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/find-the-equations-of-the-tangent-and-the-normal-at-the-point-t-on-the-curve-x-a-sin3-t-y-b-cos3-t\/","title":{"rendered":"Find the equations of the tangent and the normal at the point ‘t’ on the curve x = \\(a sin^3 t\\), y = \\(b cos^3 t\\)."},"content":{"rendered":"
We have, x = \\(a sin^3 t\\), y = \\(b cos^3 t\\)<\/p>\n
\\(\\implies\\)\u00a0 \\(dx\\over dt\\) = \\(3a sin^2t cos t\\)\u00a0 and, \\(dy\\over dt\\)\u00a0 = \\(-3b cos^2t sin t\\)<\/p>\n
\\(\\therefore\\)\u00a0 \u00a0\\(dy\\over dx\\) = \\(dy\/dt\\over dx\/dt\\) = \\(-b\\over a\\) \\(cos t\\over sin t\\)<\/p>\n
So, the equation of the tangent<\/a> at the point ‘t’ is<\/p>\n y – \\(b cos^3 t\\) = (\\(dy\\over dx\\))(x – \\(a sin^3 t\\))<\/p>\n or, y – \\(b cos^3 t\\) = \\(-b\\over a\\) \\(cos t\\over sin t\\)(x – \\(a sin^3 t\\))<\/p>\n or, bx cos t + ay sin t = ab sin t cos t<\/p>\n The equation of the normal<\/a> at the point ‘t’ is<\/p>\n y – \\(b cos^3 t\\) = \\((-1\\over ({dy\\over dx})\\)(x – \\(a sin^3 t\\))<\/p>\n or, y – \\(b cos^3 t\\) = \\((-1\\over ({-b\\over a}{cos t\\over sin t})\\)(x – \\(a sin^3 t\\))<\/p>\n or, ax sin t – by cos t = \\(a^2 sin^4 t – b^2 cos^4 t\\)<\/p>\n Find the equation of the tangent to curve y = \\(-5x^2 + 6x + 7\\)\u00a0 at the point (1\/2, 35\/4).<\/a><\/p>\n Find the equation of the normal to the curve y = \\(2x^2 + 3 sin x\\) at x = 0.<\/a><\/p>\n Find the angle between the curves xy = 6 and \\(x^2 y\\) =12.<\/a><\/p>\n Check the orthogonality of the curves \\(y^2\\) = x and \\(x^2\\) = y.<\/a><\/p>\n
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