Math Problem Statement
Solution
Let's solve the questions step by step.
The given curve is:
and point is where .
(a) Gradient of the curve at
To find the gradient of the curve at , we need to differentiate with respect to and then evaluate it at .
- Differentiate :
Using the chain rule:
- Evaluate at :
Thus, the gradient at is:
(b) Equation of the tangent to the curve at
The equation of the tangent line is given by the point-slope form: where is the gradient, and is the point of tangency.
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From part (a), the gradient .
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The point is where . Let's find at : So, the coordinates of are .
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Substitute into the equation: Simplify:
Thus, the equation of the tangent is:
(c) Coordinates of where the normal to the curve at cuts the -axis
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The gradient of the normal is the negative reciprocal of the gradient of the tangent. So, the gradient of the normal is:
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The equation of the normal is also given by the point-slope form: Simplify:
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To find the x-intercept, set : Multiply through by 3 to eliminate the fractions: Solve for :
Thus, the x-coordinate of is:
The coordinates of are .
Do you want further details or have any questions?
Here are some related questions to expand on this:
- How do you find the second derivative of ?
- Can you find the point where the curve has zero gradient?
- What is the area under the curve between and ?
- How would the equation of the tangent change if the curve was ?
- What is the significance of the normal line's x-intercept in this problem?
Tip: When dealing with logarithmic functions, remember that their derivatives follow the chain rule and are often simplified using properties of logarithms.
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Math Problem Analysis
Mathematical Concepts
Differentiation
Tangent and Normal lines
Logarithmic Functions
Formulas
Derivative of ln(3x - 1): d/dx[ln(3x - 1)] = 3/(3x - 1)
Point-slope form for tangent: y - y1 = m(x - x1)
Gradient of normal: -1/m
Theorems
Chain Rule
Point-slope form for linear equations
Suitable Grade Level
Grade 11-12 (Advanced Calculus)