Find an equation to the tangent line to a curve and parrallel

The expression d/dx(x) is a bit of a waste of time, since it means 1, and 1 times anything is itself.
  • #1
foreverlost
7
0

Homework Statement



Find an equation of the tangent line to the curve y = x√x that is parallel to the line
y = 1+3x.

Homework Equations



m = 3

The Attempt at a Solution



Here is my attempt: dy/dx(x) * dy/dx(x^(1/2)) = (1) * (1/2x^(-1/2)) = (1/2x^(-1/2))

(1/2x^(-1/2)) = 3 → x^(-1/2) = 6 → -√x = 6

x = -√36 = 6 → -6=6 -1=1

Thank you, I will not be able to respond for a bit as I am leaving for home now.
 
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  • #2
foreverlost said:

Homework Statement



Find an equation of the tangent line to the curve y = x√x that is parallel to the line
y = 1+3x.

Homework Equations



m = 3

The Attempt at a Solution



Here is my attempt: dy/dx(x) * dy/dx(x^(1/2)) = (1) * (1/2x^(-1/2)) = (1/2x^(-1/2))

(1/2x^(-1/2)) = 3 → x^(-1/2) = 6 → -√x = 6

x = -√36 = 6 → -6=6 -1=1

Thank you, I will not be able to respond for a bit as I am leaving for home now.

Two comments. First, why on Earth would you not simplify ##x\sqrt x## to ##x^\frac 3 2## before you differentiate? And given that you didn't, the product rule for differentiation is not ##(fg)' = f'g'##, which is what you did. Try again.
 
Last edited:
  • #3
To add to what LCKurtz said about your oversimplification of the product rule, what you wrote does not mean what you think.
foreverlost said:
dy/dx(x) * dy/dx(x^(1/2))
You don't take "dy/dx of x" or "dy/dx of x^(1/2)." You can take the derivative with respect to x of something, which you write as d/dx(x) + d/dx(x^(1/2)).

The expression dy/dx(x) means dy/dx times x, which I'm pretty sure isn't what you intended.
 

Related to Find an equation to the tangent line to a curve and parrallel

1. What is a tangent line to a curve?

A tangent line is a straight line that touches a curve at only one point, without crossing over the curve. It represents the instantaneous rate of change of the curve at that point.

2. How do I find the equation of a tangent line to a curve?

To find the equation of a tangent line, you first need to find the slope of the tangent line at the desired point on the curve. This can be done by taking the derivative of the curve at that point. Then, you can use the point-slope form of a line to write the equation of the tangent line.

3. Can there be more than one tangent line to a curve at a given point?

No, there can only be one tangent line to a curve at a given point. This is because the tangent line represents the instantaneous rate of change of the curve at that point, and there cannot be more than one instantaneous rate of change.

4. What is the relationship between a tangent line and a parallel line?

A parallel line has the same slope as the tangent line at a given point on the curve. This means that the parallel line will have the same instantaneous rate of change as the curve at that point.

5. How can I use tangent lines and parallel lines to solve real-world problems?

Tangent lines and parallel lines can be used to approximate the behavior of a curve at a specific point. This can be helpful in predicting future trends or making informed decisions in fields such as economics, engineering, and physics.

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