Q. For the following equation, evaluate f′(1).f(x)=−3x5+4x3−2xAnswer:
Apply Power Rule: To find the derivative of the function f(x)=−3x5+4x3−2x, we will apply the power rule to each term separately. The power rule states that the derivative of xn with respect to x is n⋅x(n−1).
Derivative of −3x5: First, we find the derivative of the term −3x5. Using the power rule, we get:dxd(−3x5)=−3×5×x5−1=−15x4.
Derivative of 4x3: Next, we find the derivative of the term 4x3. Again, using the power rule, we get:rac{d}{dx}(4x^{3}) = 4 \times 3 \times x^{3-1} = 12x^{2}.
Derivative of −2x: Finally, we find the derivative of the term −2x. The power rule for the first power is simply the coefficient, so:dxd(−2x)=−2.
Combine Derivatives: Now, we combine the derivatives of each term to get the derivative of the entire function f(x):f′(x)=−15x4+12x2−2.
Evaluate f′(1): To evaluate f′(1), we substitute x=1 into the derivative:f′(1)=−15(1)4+12(1)2−2=−15+12−2.
Perform Arithmetic: Performing the arithmetic, we get: f′(1)=−15+12−2=−5.
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