Tangent lines to parametric curves practice problems
dy/dx = (dy/dt)/(dx/dt), and the tangent line at a parameter value. 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
Find the equation of the tangent line to \( \displaystyle x = e^{t},\ y = t^{3} \) at \( \displaystyle t = 1 \).
dy/dx = (dy/dt)/(dx/dt).
Reviewed
\[ \frac{d}{d t} e^{t} = e^{t} \]
dx/dt.✓ Proved
\[ \frac{d}{d t} t^{3} = 3 t^{2} \]
dy/dt.✓ Proved
\[ \frac{3}{e} \]
The slope at t = 1.Reviewed
\[ \left[\begin{matrix}e\\1\end{matrix}\right] \]
The point.Reviewed
\[ \frac{3 x - 3 e}{e} + 1 = \frac{3 x}{e} - 2 \]
Point-slope form.✓ Proved
Answer \( y = \frac{3 x}{e} - 2 \)
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 2 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
✓ Nihil obstat Lines: 2 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
Find the equation of the tangent line to \( \displaystyle x = e^{t},\ y = 3 t + 1 \) at \( \displaystyle t = 1 \).
dy/dx = (dy/dt)/(dx/dt).
Reviewed
\[ \frac{d}{d t} e^{t} = e^{t} \]
dx/dt.✓ Proved
\[ \frac{d}{d t} \left(3 t + 1\right) = 3 \]
dy/dt.✓ Proved
\[ \frac{3}{e} \]
The slope at t = 1.Reviewed
\[ \left[\begin{matrix}e\\4\end{matrix}\right] \]
The point.Reviewed
\[ \frac{3 x - 3 e}{e} + 4 = \frac{3 x}{e} + 1 \]
Point-slope form.✓ Proved
Answer \( y = \frac{3 x}{e} + 1 \)
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 2 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
Find the equation of the tangent line to \( \displaystyle x = 2 t,\ y = t^{3} \) at \( \displaystyle t = 2 \).
dy/dx = (dy/dt)/(dx/dt).
Reviewed
\[ \frac{d}{d t} 2 t = 2 \]
dx/dt.✓ Proved
\[ \frac{d}{d t} t^{3} = 3 t^{2} \]
dy/dt.✓ Proved
\[ 6 \]
The slope at t = 2.Reviewed
\[ \left[\begin{matrix}4\\8\end{matrix}\right] \]
The point.Reviewed
\[ 6 x - 16 \]
Point-slope form.Reviewed
Answer \( y = 6 x - 16 \)
✓ Nihil obstat Lines: 2 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
Find the equation of the tangent line to \( \displaystyle x = t^{2} + 1,\ y = t^{3} \) at \( \displaystyle t = 2 \).
dy/dx = (dy/dt)/(dx/dt).
Reviewed
\[ \frac{d}{d t} \left(t^{2} + 1\right) = 2 t \]
dx/dt.✓ Proved
\[ \frac{d}{d t} t^{3} = 3 t^{2} \]
dy/dt.✓ Proved
\[ 3 \]
The slope at t = 2.Reviewed
\[ \left[\begin{matrix}5\\8\end{matrix}\right] \]
The point.Reviewed
\[ 3 x - 7 \]
Point-slope form.Reviewed
Answer \( y = 3 x - 7 \)
✓ Nihil obstat Lines: 2 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
Find the equation of the tangent line to \( \displaystyle x = 2 t,\ y = 3 t + 1 \) at \( \displaystyle t = 1 \).
dy/dx = (dy/dt)/(dx/dt).
Reviewed
\[ \frac{d}{d t} 2 t = 2 \]
dx/dt.✓ Proved
\[ \frac{d}{d t} \left(3 t + 1\right) = 3 \]
dy/dt.✓ Proved
\[ \frac{3}{2} \]
The slope at t = 1.Reviewed
\[ \left[\begin{matrix}2\\4\end{matrix}\right] \]
The point.Reviewed
\[ \frac{3 x}{2} + 1 \]
Point-slope form.Reviewed
Answer \( y = \frac{3 x}{2} + 1 \)
✓ Nihil obstat Lines: 2 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
Find the equation of the tangent line to \( \displaystyle x = \cos{\left(t \right)},\ y = \sin{\left(t \right)} \) at \( \displaystyle t = \frac{\pi}{3} \).
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 2 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
✓ Nihil obstat Lines: 2 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
Find the equation of the tangent line to \( \displaystyle x = t^{2} + 1,\ y = 3 t + 1 \) at \( \displaystyle t = 1 \).
dy/dx = (dy/dt)/(dx/dt).
Reviewed
\[ \frac{d}{d t} \left(t^{2} + 1\right) = 2 t \]
dx/dt.✓ Proved
\[ \frac{d}{d t} \left(3 t + 1\right) = 3 \]
dy/dt.✓ Proved
\[ \frac{3}{2} \]
The slope at t = 1.Reviewed
\[ \left[\begin{matrix}2\\4\end{matrix}\right] \]
The point.Reviewed
\[ \frac{3 x}{2} + 1 \]
Point-slope form.Reviewed
Answer \( y = \frac{3 x}{2} + 1 \)
✓ Nihil obstat Lines: 2 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
Answer \( y = - 3 \sqrt{2} x + \frac{3 \pi}{4} + 4 \)
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 4 proved, 2 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
✓ Nihil obstat Lines: 2 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
✓ Nihil obstat Lines: 2 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
✓ Nihil obstat Lines: 3 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
✓ Nihil obstat Lines: 2 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