Ex 10.2, 6 Find the coordinates of the focus, axis of the parabola, the equation of directrix and the length of the latus rectum for x2 = –9y Given equation is x2 = –9y. Since the above equation is involves x2 Its axis is y-axis Also coefficient of y is negative (−) Hence we use equation x2 = − 4ay Comparing x2 = −9y & x2 = −4ay From (1) & (2) −4ay = −9y a = (−9𝑦)/(−4𝑦) a = 9/4 Coordinate of focus is (0, −a) i.e. focus ("0, " (−𝟗)/𝟒) Equation of Directix is y = a y = 𝟗/𝟒 Latus Rectum is 4a = 4 × 9/4 = 9

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.