Tangent line Definition and 279 Threads

  1. K

    What are the two points on y = x^4 - 2x^2 - x with a shared tangent line?

    Hi, I am having problems with the following problem. The main issue is actually starting the problem. Find the two points on the curve y = x^4 - 2x^2 - x that have a common tangent line.
  2. J

    Tangent line approximations with trig. functions

    Find the equations of the tangent lines to the graph of f(x) = \sin x at x = 0 and at x = \frac{ \pi }{3}. Use each tangent line to approximate \sin( \frac{ \pi }{6} ) . Would you expect these results to be equally accurate, since they are taken equally far away from x = \frac{ \pi }{6}...
  3. L

    Equation of tangent line at sqrt(x)

    Hey, right now in our calculus course we are currently working on "derivatives" using the differentiation equations. I was hoping that someone could help me out with the following question: Find the equation of the tangent line to the curve at the given point. y = rootX , (4, 0.4)...
  4. V

    Solving f(x), Slope & Tangent Line: Help Me Find Answers!

    can you guys help me how to do this problem? f(x) = 3x^2 - 1 (3,8) Find slope and tangent line, I have answer 6, is that right? and can you guys show the step to get the answer, thanks =) (tangent line i already know how to do) oh and this one, y = x^2 - 4 Find...
  5. B

    Find k for Tangent Line of f(x) = x^2 - kx

    Hi, I need help on a math problem that asks me to find k such that the line is tangent to the function, givenf(x) = x^2 - kx and y = 4x - 9. I don't know how to solve for k. Is "tangent line" the same thing as the equation that is the derivative of the function?
  6. R

    Use calculus to find the slope of the tangent line

    I'm given f(x) = x^2 and g(x) = -x^2 + 2x - 5 And it says Let A (a, f(a)) be the point of tangency on f(x) and B (b, g(b)) be the point of tangency on g(x). Use calculus to find the slope of the tangent line at each point. What must be true about these two slope expressions? I know we...
  7. D

    Slope of Tangent Line for y = sin(2πx) at x = 1 and x = 2

    really isn't calculus but that's the name of my class so, anyway I am having a problem here. i think its pretty simple I am just missing something. I am supposed to find the slope of the tangent line using one point and: slope of tangent line = \frac{f(a+h)-f(a)}{h} h\rightarrow0...
  8. mbrmbrg

    Given a tangent line, find f(x)

    I have a homework problem as follows: If the tangent line to y = f(x) at (4,3) passes through the point (0,2), find f(4) and f'(4). Using the slope formula and the point-slope formula, I found that the equation of the given tangent line is y = 1/4x + 2. Now I want to find f(x) so I can...
  9. S

    What is the equation of the tangent line for f(x) = \frac {2x-5}{x+1} at x = 0?

    Can someone check if I did this right: Find the equation of the tangent line to the graph of f(x) = \frac {2x-5}{x+1} at the point at which x = 0. f(x) = \frac {2(0) - 5}{(0) + 1} = -5 So I got y = -5 Then I wanted to find the derivative of the original using the quotient rule to find...
  10. E

    How to Find the Vector Equation of a Tangent Line to a Curve at a Given Point

    Can anybody help me out with this Q? "A curve R in space has vector equation: x = (sin(\pi u), u^2 - 1, u^2 + 3u + 3) u is a real number. Find a vector equation of the tangent line to R at the point (0, 0, 1)"
  11. M

    No Tangent Line: Graph of y = |x| Explained

    Am I thinking right about this following question: Give a geometric argument to show that the graph of y = lxl has no tangent line at the point (0,0). Since that graph would be basically the bisectors of the 1st and second quadrants, why can't the x-axis be that tangent line? (def. of a...
  12. C

    Finding the Tangent Line for f'(x): Solving for General Form

    Okay so i have f(x) I want to find f'(x) it's derivative F'(x) is the slope So let's say they ask for the tangent line to the point on the graph where x=2. I replace x by 2 in my derived equation and isolate Y. Let's say i found that Y=5 Now I need to find the equation of the Tangent...
  13. M

    Parametric Curves and Tangent line equations

    Find an equation of the tangent line to the curve with parametric equations x=tsint, y=tcost at the point (0,-π). went dy/dt / dx/dt --> cost - tsint/sint + tcost t not given so figured it could be: x=t(sin(1)) --> t= x/sin(1) or y=t(cos(1)) --> t= y/cos(1) wondering if...
  14. J

    Solving Tangent Line Problems for Quartics & Beyond

    Need Help Please! Tangent Line Problems! Hey, Okay, so here's the problem. I've got this quartic: 0 = -9x^4 + 190x^3 + 840x^2 + 1992x I need to find if this graph has two or more points with the same tangent line, and I'm at a loss. Given a point, I have no problem finding the tangent...
  15. V

    Tangent line at y = 9/sqrt(1+x)

    Find the y-intercept of the tangent line to the graph of y = (9)/sqrt(1 + x) at the point where x = 9. I used the quotient rule to find the derivative. I found that to be (-9/2(1+x)^-1/2)/(1+x) But then I am totally clued out... Thanks for helping me out. volc
  16. M

    Finding parametric equations for the tangent line

    Hello everyone, I'm having troubles seeing how this works. The directions are: Find parametric equations for the tagent line to the curve with the given parametric equations at the specified point. Here is my work and problem...
  17. B

    Tangent line to a particles path at a specific time?

    how do you find orientation of a line that is tangent to the particle's path at t = 2.10 s?(from the +x axis) before this i found the position r of a particle moving in an xy plane is given by r = (1.00t3 - 8.00t) i + (7.00 - 4.00t4) j. So I found r,v,a, for t=2.10s (all in m) r=-7.54 i...
  18. W

    Parametric equations for the tangent line

    Find parametric equations for the tangent line at the point (cos(-4pi/6),sin(-4pi/6),-4pi/6) on the curve x=cost, y=sint,z=t x(t) = _________ y(t) = _________ z(t) = _________ r'(t) = <-sin(t), cos(t), 1> r'(0) = <0,1,1> my answer: x = cos(-4pi/6) + 0t y = sin(-4pi/6) +1t z =...
  19. V

    Finding Tangent Line to f(x) at (4, (2/5))

    I need to find an equation for the tangent line to the graph of the function at the specified point, I had some trouble simplifing f(x) so that I can take the lim as h->0 which is the slope. f(x) = Sqrt(x)/5 at (4,(2/5))
  20. V

    Finding Tangent Line of f(x) at (4,(2/5))

    I need to find an equation for the tangent line to the graph of the function at the specified point, I had some trouble simplifing f(x) so that I can take the lim as x->0 which is the slope. f(x) = Sqrt(x)/5 at (4,(2/5))
  21. E

    How Do You Determine the Slope of a Tangent Line for the Curve 2cy = x^2 - c^2?

    Here's the problem: detrmine DE giving the slope of the tangent line at point (x,y) for the given family of curves: 2cy = x^2 - c^2 Here's what I have: slope of this curve: y' = \frac{x}{c} So, then the slope of tangent line is negative inverse: y' = \m \frac{-c}{x}...
  22. G

    Find the equation of the tangent line to the graph

    i just want to check my answers...coz i don't have an answer key to compare with... 1) y^2-3xy+x^2=7 y'=3y-2x/2y-3x 2) x^2+y^2=2xy y'=1 3) 2x^2+xy+3y^2=0 y'=-4x-y/x+6y 4) 5x^2-2xy+7y^2=0 y'=y-5x/7y-x 5) 7x^2+6xy+9y^2=0 y'=-7x-3y/3x+9y 6) Find the equation of the tangent line...
  23. C

    Equations of Tangent Lines Passing Through Point P(5,5) for y = x^2 - 4

    Hello all Find the equations of all lines tangent to y = x^2 - 4 that pass through the point P(5,5) My solution: If f(x) = x^2 - 4 then f'(x) = 2x . So y - 5 = 10(x-5) This is just tthe equation of 1 tangent line. To find all tangent lines would I have to add some constant...
  24. C

    Is Y=23x+18 the Correct Equation for the Tangent Line at X=2?

    Find the equation of the tangent line at x=2 F(X)=2x+7x(e^(x-2)) I know you put 2 into find the y intercept and you take the derivative to find the slope. I get 2+(7e^(-2)x + 7e^-2)e^2 for my derivative and y=23x+18 as my answer and i know that is not correct.
  25. T

    Parallel Tangent Line to y=(x-1)/(x+1)

    Find the equations of the tangent line to the curve y= (x-1)/(x+1) that are parallel to the line x-2y=2 help!
  26. D

    Find parametric equations for the tangent line to the curve at t=1

    Original question: a) Say r'(t) = 3t^2 i - cost j + 2t k, and r(0) = i + k. Find r(t). b) Find T(t). c) Find parametric equations for the tangent line to the curve at t=1. I have done parts a and b and got the following results: a) r(t) = t^3 + 1 i - sint j + t^2 + 1 k b)T(t) =...
  27. U

    Equation of Tangent Line to y=cosx at a=pi/4

    Write the equation of the tangent line to the cure y=cosx at a=pi/4 (y-y1)=m(x-x1) cos(pi/4)=sqrt(2)/2 y'=-sinx=-sin(pi/4)=-sqrt(2)/2 (y-sqrt(2)/2)=m(x-pi/4) y'=-sqrt(2)/2(x-pi/4)+sqrt(2)/2 My teacher circled the y' and took a point off. I know that y'=-sinx but what should be in...
  28. C

    Calculus Problem (involving tangent line)

    Here is exactly how the problem reads: 53. Find an equation of the tangent line to the graph of F at the indicated point. y = x^4 - 3x^2 + 2 (1,0) I'll be honest. I do not understand how to do these type problems. I've been reading this section of the book over and over to...
  29. N

    Finding the Equation of a Tangent Line at a Given Point

    I need to know how to find the equation of the tangent line to the graph of the equation y = xe^(1/x^2) + ln(3 - 2x^2) at the point (1, e). Admittedly, I have no idea at all what the question is asking for and I don't have the slighest clue on how to solve this question. Any help will be greatly...
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