A curve C is described by the equation
3x^2 - 2y^2 + 2x - 3y + 5 = 0 - Edexcel - A-Level Maths Pure - Question 3 - 2006 - Paper 6
Question 3
A curve C is described by the equation
3x^2 - 2y^2 + 2x - 3y + 5 = 0.
Find an equation of the normal to C at the point (0, 1), giving your answer in the form ax + b... show full transcript
Worked Solution & Example Answer:A curve C is described by the equation
3x^2 - 2y^2 + 2x - 3y + 5 = 0 - Edexcel - A-Level Maths Pure - Question 3 - 2006 - Paper 6
Step 1
Differentiate the equation implicitly
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Answer
To find the normal, we first need to differentiate the equation of the curve implicitly. Differentiating both sides gives:
6x−4ydxdy+2+2x−3dxdy=0
This simplifies to:
6x+2−(4y+3)dxdy=0
Step 2
Find the derivative at the point (0, 1)
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Answer
Next, we substitute the point (0, 1) into the derivative:
At (0, 1):
6(0)+2−(4(1)+3)dxdy=0
This simplifies to:
2−7dxdy=0
Thus:
dxdy=72
Step 3
Determine the slope of the normal
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Answer
The slope of the normal line is the negative reciprocal of the derivative:
mnormal=−721=−27
Step 4
Formulate the equation of the normal
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Answer
Using the point-slope form of the equation of a line, we have:
y−1=mnormal(x−0)
Substituting the value of the normal slope:
y−1=−27(x)
This can be rearranged to:
7x+2y−2=0
Thus, in the form ax + by + c = 0, we have a = 7, b = 2, c = -2.