dy/dx when y is tangled up with x in an equation. 70 problems with worked solutions; in 70 of them every
equation is proved by a computer algebra system.
20 worked problems
Try each one before opening the solution. Every line is labeled with what checked it. How we verify
The curve \( \displaystyle - 2 x + y + \sin{\left(x y \right)} = 3 - \sin{\left(1 \right)} \) passes through \( \displaystyle (-1, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 - \sin{\left(1 \right)} \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 1}, \quad \left.\frac{dy}{dx}\right|_{(-1,1)} = \frac{2 - \cos{\left(1 \right)}}{1 - \cos{\left(1 \right)}} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 2 x + 4 y + \sin{\left(x y \right)} = \sin{\left(1 \right)} + 2 \) passes through \( \displaystyle (1, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ \sin{\left(1 \right)} + 2 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 4}, \quad \left.\frac{dy}{dx}\right|_{(1,1)} = \frac{2 - \cos{\left(1 \right)}}{\cos{\left(1 \right)} + 4} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 2 x + y + \sin{\left(x y \right)} = -3 + \sin{\left(2 \right)} \) passes through \( \displaystyle (2, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ -3 + \sin{\left(2 \right)} \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 1}, \quad \left.\frac{dy}{dx}\right|_{(2,1)} = \frac{2 - \cos{\left(2 \right)}}{2 \cos{\left(2 \right)} + 1} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 3 x + 4 y + \sin{\left(x y \right)} = 7 - \sin{\left(1 \right)} \) passes through \( \displaystyle (-1, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 7 - \sin{\left(1 \right)} \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 3}{x \cos{\left(x y \right)} + 4}, \quad \left.\frac{dy}{dx}\right|_{(-1,1)} = \frac{3 - \cos{\left(1 \right)}}{4 - \cos{\left(1 \right)}} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 2 x + 4 y + \sin{\left(x y \right)} = -6 - \sin{\left(1 \right)} \) passes through \( \displaystyle (1, -1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ -6 - \sin{\left(1 \right)} \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 4}, \quad \left.\frac{dy}{dx}\right|_{(1,-1)} = \frac{\cos{\left(1 \right)} + 2}{\cos{\left(1 \right)} + 4} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - x + 2 y + \sin{\left(x y \right)} = 3 - \sin{\left(1 \right)} \) passes through \( \displaystyle (-1, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 - \sin{\left(1 \right)} \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 1}{x \cos{\left(x y \right)} + 2}, \quad \left.\frac{dy}{dx}\right|_{(-1,1)} = \frac{1 - \cos{\left(1 \right)}}{2 - \cos{\left(1 \right)}} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle x^{3} + 2 x y + y^{3} = -2 \) passes through \( \displaystyle (1, -1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ -2 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle 3 x^{2} + 3 x y + 3 y^{2} = 3 \) passes through \( \displaystyle (0, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
✓ Nihil obstat Lines: 2 proved, 3 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle x^{2} y - 3 x + y^{3} = 1 \) passes through \( \displaystyle (0, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 1 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- 2 x y + 3}{x^{2} + 3 y^{2}}, \quad \left.\frac{dy}{dx}\right|_{(0,1)} = 1 \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 2 x + 3 y + \sin{\left(x y \right)} = 3 \) passes through \( \displaystyle (0, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
\[ \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 3} \]
Solve for dy/dx: minus F_x over F_y.Reviewed
\[ 1 \cdot \frac{1}{3} = \frac{1}{3} \]
At the point.Reviewed
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 3}, \quad \left.\frac{dy}{dx}\right|_{(0,1)} = \frac{1}{3} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle 3 x^{2} - 2 x y + 2 y^{2} = 3 \) passes through \( \displaystyle (1, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
✓ Nihil obstat Lines: 2 proved, 3 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 2 x + 3 y + \sin{\left(x y \right)} = -2 \) passes through \( \displaystyle (1, 0) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ -2 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
\[ \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 3} \]
Solve for dy/dx: minus F_x over F_y.Reviewed
\[ 1 \cdot \frac{1}{2} = \frac{1}{2} \]
At the point.Reviewed
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 2}{x \cos{\left(x y \right)} + 3}, \quad \left.\frac{dy}{dx}\right|_{(1,0)} = \frac{1}{2} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - x + y + \sin{\left(x y \right)} = 2 - \sin{\left(1 \right)} \) passes through \( \displaystyle (-1, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 2 - \sin{\left(1 \right)} \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
\[ \frac{- y \cos{\left(x y \right)} + 1}{x \cos{\left(x y \right)} + 1} \]
Solve for dy/dx: minus F_x over F_y.Reviewed
\[ 1 \]
At the point.Reviewed
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 1}{x \cos{\left(x y \right)} + 1}, \quad \left.\frac{dy}{dx}\right|_{(-1,1)} = 1 \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle x^{3} - 2 x y + y^{3} = 5 \) passes through \( \displaystyle (2, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 5 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
✓ Nihil obstat Lines: 2 proved, 3 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle x^{2} y - 2 x + 3 y^{3} = -2 \) passes through \( \displaystyle (1, 0) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ -2 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{2 \left(- x y + 1\right)}{x^{2} + 9 y^{2}}, \quad \left.\frac{dy}{dx}\right|_{(1,0)} = 2 \)
✓ Nihil obstat Lines: 2 proved, 3 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle - 4 x + y + \sin{\left(x y \right)} = 1 \) passes through \( \displaystyle (0, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 1 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
\[ \frac{- y \cos{\left(x y \right)} + 4}{x \cos{\left(x y \right)} + 1} \]
Solve for dy/dx: minus F_x over F_y.Reviewed
\[ 3 \]
At the point.Reviewed
Answer \( \frac{dy}{dx} = \frac{- y \cos{\left(x y \right)} + 4}{x \cos{\left(x y \right)} + 1}, \quad \left.\frac{dy}{dx}\right|_{(0,1)} = 3 \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle 3 x^{2} - x y + 3 y^{2} = 3 \) passes through \( \displaystyle (0, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
✓ Nihil obstat Lines: 2 proved, 3 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle 3 x^{2} + 2 x y + y^{2} = 1 \) passes through \( \displaystyle (0, 1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 1 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
✓ Nihil obstat Lines: 2 proved, 3 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle 4 x^{2} + 3 x y + 2 y^{2} = 3 \) passes through \( \displaystyle (1, -1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ 3 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- 8 x - 3 y}{3 x + 4 y}, \quad \left.\frac{dy}{dx}\right|_{(1,-1)} = 5 \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify
The curve \( \displaystyle x^{2} y - x + y^{3} = -3 \) passes through \( \displaystyle (1, -1) \). Find \( \displaystyle \dfrac{dy}{dx} \) by implicit differentiation, and its value at that point.
\[ -3 \]
The point is on the curve.Reviewed
Differentiate both sides with respect to x, treating y as a function of x, then solve for dy/dx.
Answer \( \frac{dy}{dx} = \frac{- 2 x y + 1}{x^{2} + 3 y^{2}}, \quad \left.\frac{dy}{dx}\right|_{(1,-1)} = \frac{3}{4} \)
✓ Nihil obstat Lines: 1 proved, 4 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt ·
How we verify