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Transcript

Ex 7.2, 5 Find the ratio in which the line segment joining A(1, – 5) & B (– 4, 5) is divided by the x−axis. Also find the coordinates of the point of division. Now, we have to find ratio Let ratio be k : 1 Hence, m1 = k, m2 = 1 x1 = 1, y1 = −5 Note: Point P is on x−axis, hence its y coordinate is 0. So, it is of the form P(x, 0) x2 = −4, y2 = 5 Also, x = x, y = 0 Using section formula y = (𝑚_1 𝑦_2 + 𝑚_2 𝑦_1)/(𝑚_1+𝑚_2 ) 0 = (𝑘 ×5 + 1 ×−5)/(𝑘 + 1) 0 = (5𝑘 −5)/(𝑘 +1) 0(k + 1)= 5k – 5 0 = 5k – 5 5k – 5 = 0 5k = 5 k = 5/5 k = 1 Hence, Ratio is = k : 1 = 1 : 1 Now, we need to find x also x = (𝑚1 𝑥2 + 𝑚2 𝑥1)/(𝑚1 + 𝑚2) = (𝑘 × −4 + 1 × 1)/(𝑘 + 1) = (1 ×−4 + 1 × 1)/(1 + 1) = (−4 + 1)/2 = (−3)/2 Hence the coordinate of point is P(x, 0) = P ((−𝟑)/𝟐 ", 0" )

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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 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.