Let AB be divided by the x-axis in the ratio k : 1 at the point P. Then, by section formula the coordination of P are `p = ((5k+2)/(k+1),(6k-3)/(k+1))` But P lies on the x-axis; so, its ordinate is 0. Therefore , `(6k-3)/(k+1) = 0` `⇒ 6k -3=0 ⇒ 6k =3 ⇒k = 3/6 ⇒ k = 1/2` Therefore, the required ratio is `1/2:1 `, which is same as 1 : 2 Thus, the x-axis divides the line AB li the ratio 1 : 2 at the point P. Applying `k=1/2` we get the coordinates of point. `p((5k+1)/(k+1) , 0)` `=p((5xx1/2+2)/(1/2+1),0)` `= p (((5+4)/2)/((5+2)/2),0)` `= p (9/3,0)` = p (3,0) Hence, the point of intersection of AB and the x-axis is P( 3,0). Page 2Let AB be divided by the x-axis in the ratio :1 k at the point P. Then, by section formula the coordination of P are `p = ((3k-2)/(k+1) , (7k-3)/(k+1))` But P lies on the y-axis; so, its abscissa is 0. `⇒ 3k-2 = 0 ⇒3k=2 ⇒ k = 2/3 ⇒ k = 2/3 ` Therefore, the required ratio is `2/3:1`which is same as 2 : 3 Applying `k= 2/3,` we get the coordinates of point. `p (0,(7k-3)/(k+1))` `= p(0, (7xx2/3-3)/(2/3+1))` `= p(0, ((14-9)/3)/((2+3)/3))` `= p (0,5/5)` = p(0,1) Hence, the point of intersection of AB and the x-axis is P (0,1). Open in App 6k−3k+1=0
Thus, x-axis divides the line segment joining the points (2, –3) and (5,6) in the ratio 1:2. Suggest Corrections 83
Question 5 Coordinated Geometry - Exercise 7.3 Next
Answer:
Let the ratio in which x-axis divides the line segment joining (–4, –6) and (–1, 7) = 1: k. Then, x-coordinate becomes, \frac{\left(-1-4k\right)}{(k+1)} y-coordinate becomes, \frac{\left(7-6k\right)}{(k+1)} Since P lies on x-axis, y coordinate = 0 \frac{\left(7-6k\right)}{(k+1)}=0\\ 7-6k=0\\ k=\frac{7}{6} Therefore, the point of division divides the line segment in the ratio 6 : 7. Now, m1 = 6 and m2 = 7 By using the section formula, x=\frac{\left(m_1x_2+m_2x_2\right)}{(m_1+m_2)}=\frac{\left[6(-1)+7(-4)\right]}{(6+7)}=\frac{\left(-6-28\right)}{13}=-\frac{34}{13}\\ So,\ now\\ y=\frac{\left[6(7)+7(-6)\right]}{(6+7)}=\frac{\left(42-42\right)}{13}=0 Hence, the coordinates of P are (-34/13, 0)
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