The Plane 2m Questions & Solutions || V.S.A.Q’S||
The Plane 2m Questions & Solutions || V.S.A.Q’S|| The Plane 2m Questions: The Plane: These solutions were designed by the ‘Basics in Maths’ team. These notes to do help intermediate First-year Maths students. Inter Maths – 1B two mark questions and solutions are very useful in IPE examinations. These notes cover all the topics covered in the intermediate First-year Maths syllabus and include plenty of solutions to help you solve all the major types of Math problems asked in the IPE examinations. The Plane Question 1 Find the equation of the plane if the foot of the perpendicular from the origin to the plane is (2, 3, – 5). Sol: The plane passes through A and is perpendicular to OA, then the line segment OA is normal to the plane. Dr’s of OA = (2, 3, – 5) The equation of the plane passing through the point (x1, y1, z1) and dr’s (a, b, c) is a(x – x1) + b (y – y1) + c (z – z1) = 0 ⟹ 2(x – 2) + 3 (y – 3) – 5 (z + 5) = 0 2x – 4 + 3y – 9 – 5z – 25 = 0 2x + 3y – 5z – 38 = 0 Question 2 Find the equation of the plane passing through the points (0, – 1, – 1), (4, 5, 1) and (3, 9, 4) Sol: The equation of the plane passing through the points (x1, y1, z1) (x2, y2, z2) (x3, y3, z3) is The plane passing through the points (0, – 1, – 1), (4, 5, 1) and (3, 9, 4) is =0 ⟹ = 0 x (30 – 20) – (y + 1) (20 – 6) + (z + 1) (40 – 18) = 0 x (10) – (y + 1) (14) + (z + 1) (22) = 0 10x – 14y – 14 + 22z + 22 = 0 10x – 14y + 22z + 8 = 0 2(5x – 7y + 11z + 4) = 0 ∴ the equation of the plane is 5x – 7y + 11z + 4 = 0 Question 3 Find the equation to the plane parallel to the ZX-plane and passing through (0, 4, 4). Sol: Equation of ZX-plane is y = 0 The equation of the plane parallel to the ZX-plane is y = k But it is passing through (0, 4, 4) ⟹ y = 4 Question 4 Find the equation to the plane passing through the point (α, β, γ) and parallel to the plane axe + by + cz + d = 0. Sol: The equation of the plane parallel to the plane ax + by + cz + d = 0 is ax + by + cz + k = 0 But it is passing through the point (α, β, γ) a α + b β + c γ + k = 0 ⟹ k = – a α – b β – c γ The equation of the plane is ax + by + cz – a α – b β – c γ = 0 ⟹ a(x – α) + b (y – β)+ c (z – γ) = 0 The Plane 2m Questions Question 5 Find the angle between the planes 2x – y + z = 6 and x + y + 2z = 7. Sol: If θ is the angle between the planes a1 x + b1 y + c1 z + d1 = 0 and a2x + b2 y + c2 z + d2 = 0, then cos θ = Cos θ = = = Cos θ = cos 600 θ = 600 = Question 6 Reduce the equation x + 2y – 2z – 9 = 0 to the normal form and hence find the dc’s of the normal to the plane. Sol: Given plane is x + 2y – 2z – 9 = 0 x + 2y – 2z = 9 dividing into both sides by the normal form is dc’s of the normal to the plane are Question 7 Suppose a plane makes intercepts 2, 3, 4 on X, Y, Z axes respectively. Find the equation of the plane in the intercept form. Sol: Given a = 2, b = 3, c = 4 The equation of the line in the intercept form is ⟹ Question 8 Express x – 3y + 2z = 9 in the intercept form Sol: Given plane is x – 3y + 2z = 9 ⟹ ⟹ It is in the form of a = 9, b = – 3, c = 9/2 The Plane 2m Questions Question 9 Find the direction cosine of the normal to the plane x + 2y + 2z – 4 = 0. Sol: Given plane is x + 2y + 2z – 4 = 0 We know that Dr’s of the normal to the plane ax + by + cz + d = 0 are (a, b, c) ⟹ dc’s of the normal to the plane = ⟹ dr’s of the normal to the plane x + 2y + 2z – 4 = 0 are (1, 2, 2) ⟹ dc’s of the normal to the plane are = Question 10 Find the midpoint of the line joining the points (1, 2, 3) and (–2, 4, 2) Sol: Given points are A (1, 2, 3), B (–2, 4, 2) The midpoint of AB = = = Visit my Youtube Channel: Click on Below Logo
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