Q. find the points on the parabola 2x+y2=0 closest to the point (−3,0)
Use Distance Formula: We need to minimize the distance from the point (−3,0) to any point (x,y) on the parabola 2x+y2=0.Use the distance formula: D=(x−(−3))2+(y−0)2.
Simplify Formula: Simplify the distance formula: D=(x+3)2+y2.
Minimize Distance: To find the minimum distance, we can minimize D2 to avoid the square root: D2=(x+3)2+y2.
Substitute y2: Substitute y2 from the parabola equation into D2: D2=(x+3)2+(−2x).
Expand and Simplify: Expand and simplify: D2=x2+6x+9−2x.
Combine Like Terms: Combine like terms: D2=x2+4x+9.
Take Derivative: To find the minimum, take the derivative and set it to zero: dxd(D2)=2x+4.
Set Derivative to Zero: Set the derivative equal to zero and solve for x: 2x+4=0.
Solve for x: Solve for x: x=−24.
Substitute Back: Solve for x: x=−2.
Find y: Substitute x back into the parabola equation to find y: 2(−2)+y2=0.
Closest Points: Solve for y2: y2=4.
Closest Points: Solve for y2: y2=4. Find y: y=±2.
Closest Points: Solve for y2: y2=4. Find y: y=±2. The closest points on the parabola are (−2,2) and (−2,−2).