Questions
Question 1
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Write the first-principles definition of \(f'(x)\).
Question 2
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In \(\frac{f(x+h)-f(x)}{h}\), what does \(h\) represent?
Question 3
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For \(f(x)=x^2\), write \(f(x+h)\).
Question 4
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For \(f(x)=3x+1\), write the difference quotient \(\frac{f(x+h)-f(x)}{h}\).
Question 5
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Use first principles to differentiate \(f(x)=2x\).
Question 6
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Use first principles to differentiate \(f(x)=x+4\).
Question 7
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Use first principles to differentiate \(f(x)=x^2\).
Question 8
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Use first principles to differentiate \(f(x)=x^2+3\).
Question 9
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Use first principles to differentiate \(f(x)=x^3\).
Question 10
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Use first principles to find the derivative of \(f(x)=5-x^2\).
Question 11
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Use the alternative first-principles form to find \(f'(2)\) for \(f(x)=x^2+1\).
Question 12
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Explain why the factor \(h\) must be cancelled before setting \(h=0\) in a first-principles derivative.
Question 13
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Use first principles to differentiate \(f(x)=1/x\) for \(x\ne0\).
Question 14
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Use first principles to differentiate \(f(x)=\sqrt{x}\) for \(x>0\).
Question 15
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For \(f(x)=ax^2\), use first principles to find \(a\) if \(f'(3)=18\).
Question 16
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Use first principles to find \(f'(0)\) for \(f(x)=|x|\), or explain why it does not exist.
Question 17
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For \(f(x)=x^2+kx\), use first principles to find \(k\) if \(f'(1)=7\).
Question 18
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A student substitutes \(h=0\) into \(\frac{(x+h)^2-x^2}{h}\) and says the derivative is undefined. Diagnose the error.
Question 19
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Use first principles to show that the derivative of a constant function \(f(x)=c\) is zero.
Question 20
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Using first principles, explain why a corner in a graph can prevent differentiability.