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Ch. 3 - Derivatives
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 3, Problema 51

Assume that functions f and g are differentiable with f(1) = 2, f'(1) = −3, g(1) = 4, and g'(1) = −2. Find the equation of the line tangent to the graph of F(x) = f(x)g(x) at x = 1.

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To find the equation of the tangent line to the graph of F(x) = f(x)g(x) at x = 1, we first need to determine the value of F(1). Since F(x) = f(x)g(x), we can substitute x = 1 to get F(1) = f(1)g(1). Given that f(1) = 2 and g(1) = 4, calculate F(1) = 2 * 4.
Next, we need to find the derivative of F(x) = f(x)g(x) using the product rule. The product rule states that if F(x) = f(x)g(x), then F'(x) = f'(x)g(x) + f(x)g'(x).
Substitute the given values into the derivative formula. We have f'(1) = -3, g(1) = 4, f(1) = 2, and g'(1) = -2. Therefore, F'(1) = f'(1)g(1) + f(1)g'(1) = (-3)(4) + (2)(-2).
Now that we have F(1) and F'(1), we can write the equation of the tangent line. The general form of the equation of a tangent line is y = F'(1)(x - 1) + F(1).
Substitute the values of F(1) and F'(1) into the tangent line equation to express the equation of the tangent line at x = 1.

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Product Rule

The product rule is a fundamental differentiation rule used when finding the derivative of a product of two functions. If F(x) = f(x)g(x), then the derivative F'(x) is given by f'(x)g(x) + f(x)g'(x). This rule is essential for determining the slope of the tangent line to the graph of F(x) at a specific point.
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The Product Rule

Tangent Line Equation

The equation of a tangent line to a curve at a given point is derived using the point-slope form: y - y₁ = m(x - x₁), where m is the slope of the tangent line and (x₁, y₁) is the point of tangency. For F(x) = f(x)g(x), the slope m is F'(1), and the point is (1, F(1)).
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Percorso guidato
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Equations of Tangent Lines

Function Evaluation

Function evaluation involves substituting a specific value into a function to find its output. For F(x) = f(x)g(x), evaluating F(1) requires calculating f(1)g(1). This step is crucial for determining the y-coordinate of the point of tangency, which is needed for the tangent line equation.
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Percorso guidato
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Evaluating Composed Functions
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