Q. For the function f(x)=−7x2+3x−5, find the slope of the tangent line at x=3.Answer:
Find Derivative: To find the slope of the tangent line to the function at a specific point, we need to find the derivative of the function, which gives us the slope of the tangent line at any point x. The function is f(x)=−7x2+3x−5. We will use the power rule for differentiation, which states that the derivative of xn is n⋅x(n−1).
Apply Power Rule: Differentiate the function with respect to x. The derivative of −7x2 is −14x (using the power rule, bringing down the exponent 2 and subtracting 1 from the exponent). The derivative of 3x is 3 (since the derivative of x is 1). The derivative of a constant, −5, is −7x20 (since constants do not change and their derivative is always −7x20). So, the derivative −7x22 is −7x23.
Evaluate at x=3: Now we need to evaluate the derivative at x=3 to find the slope of the tangent line at that point.Substitute x=3 into the derivative f′(x)=−14x+3.f′(3)=−14(3)+3=−42+3=−39.
Calculate Slope: The slope of the tangent line at x=3 is −39.
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