Example 1 : <\/span> The length of latus rectum of a parabola, whose focus is (2, 3) and directrix is the line x – 4y + 3 = 0 is –<\/p>\n Solution : <\/span>The length of latus rectum = 2 x perp. from focus to the dirctrix Example 2 : <\/span> Find the value of k for which the point (k-1, k) lies inside the parabola \\(y^2\\) = 4x.<\/p>\n Solution : <\/span>\\(\\because\\) Point (k-1, k) lies inside the parabola \\(y^2\\) = 4x. Example 3 : <\/span> Find the equation of the tangents to the parabola \\(y^2\\) = 9x which go through the point (4,10).<\/p>\n Solution : <\/span>Equation of tangent to the parabola \\(y^2\\) = 9x is Example 4 : <\/span> Find the locus of middle point of the chord of the parabola \\(y^2\\) = 4ax which pass through a given (p,q).<\/p>\n Solution : <\/span>Let P(h,k) be the mid point of chord of the parabola \\(y^2\\) = 4ax, Practice these given parabola examples to test your knowledge on concepts of parabola.<\/p>\n \n <\/div>\n <\/div>\n","protected":false},"excerpt":{"rendered":" Here you will learn some parabola examples for better understanding of parabola concepts. Example 1 : The length of latus rectum of a parabola, whose focus is (2, 3) and directrix is the line x – 4y + 3 = 0 is – Solution : The length of latus rectum = 2 x perp. from …<\/p>\n
\n = 2 x |\\({2-4(3)+3}\\over {\\sqrt{1+16}}\\)| = \\(14\\over \\sqrt{17}\\)<\/p>\n
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\\(\\therefore\\) \\({y_1}^2 – 4ax_1\\) < 0
\\(\\implies\\) \\(k^2\\) – 4(k-1) < 0
\\(\\implies\\) \\(k^2\\) – 4k + 4 < 0
\\((k-2)^2\\) < 0 \\(\\implies\\) k \\(\\in\\) \\(\\phi\\)\n <\/p>
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y = mx + \\(9\\over 4m\\)
Since it passes through (4,10)
\\(\\therefore\\) 10 = 4m + \\(9\\over 4m\\) \\(\\implies\\) 16\\(m^2\\) – 40m + 9 = 0
m = \\(1\\over 4\\), \\(9\\over 4\\)
\\(\\therefore\\) Equation of tangent’s are y = \\(x\\over 4\\) + 9 & y = \\(9x\\over 4\\) + 1<\/p>\n
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so equation of chord is yk – 2a(x+h) = \\(k^2\\) – 4ah.
Since it passes through (p,q)
\\(\\therefore\\) qk – 2a(p+h) = \\(k^2\\) – 4ah
\\(\\therefore\\) Required locus is \\(y^2\\) – 2ax – qy + 2ap = 0<\/p>\n
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