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Homework Help: Calculus - find dy/dt thank you

  1. Apr 6, 2005 #1
    calculus -.. find dy/dt...thank you..:(

    can someone plz help me out with this question...i did it all sorts of way,quotient rule, product rule..etc.. but i can never match the answer in the book..i just wanna know if u did..

    find dy/dt = x^2 Tanx / sec x

    The answer in the book was
    x(xcosx + 2sinx)

    lemmi know how you did it with a couple steps! thanks soo mcuh
     
  2. jcsd
  3. Apr 6, 2005 #2
    Do you mean find

    [tex] \frac{d}{dx} \frac{x^2 \tan{x}}{\sec{x}}[/tex]

    ?

    If so, here:

    [tex]\frac{x^2 \tan{x}}{\sec{x}} = x^2\tan{x}\cos{x} = x^2 \frac{\sin{x}}{\cos{x}}\cos{x} = x^2 \sin{x}[/tex]

    I'm sure you can take the derivative from there~ :smile:
     
  4. Apr 6, 2005 #3
    Damn you Data! :smile:
     
  5. Apr 6, 2005 #4
    got to be quick :tongue:
     
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