Recent content by BrianHare

  1. B

    Equation of tagent line when x is given, but not Y.

    Homework Statement Find the equation of the line tangent to y=(x²+3x)² (2x-2)³, when x=8 Homework Equations The Attempt at a Solution dy/dx = 56x^6+144x^5-240x^4-320x^3+504x^2-144x...or...8x(x+3)(x+2)(7x-3)(x-1)² dy/dx (8) = 18282880 y(x) = 21249536 Equation of tangent line at x=8; y=...
  2. B

    Finding a value to make piecewise continuous

    My teacher has a definition where \lim_{x\to a}f(x) = f(c) It was my understanding that f(x) = 3x^2, a = -5, and f(c) = 2x+c. So once I knew the answer to the limit, i knew that f(c) = 75, thus 2x+c must also be 75. Maybe I am misunderstanding the definition. Can anyone clarify?
  3. B

    Finding a value to make piecewise continuous

    Homework Statement Find c such that it makes f(x) continuous. Homework Equations f(x)=\begin{cases} 2x+c&x < -5\\ 3x^2&-5 \leq x < 0\\ cx^2&0 \leq x\\ \end{cases} The Attempt at a Solution I know that \lim_{x\to 5^-}3x^2 = 2x+c and \lim_{x\to...
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