WJEC Unit 1 2019 June — Question 08 8 marks

Exam BoardWJEC
ModuleUnit 1 (Unit 1)
Year2019
SessionJune
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicDifferentiation from First Principles
TypeFirst principles: polynomial with multiple terms
DifficultyStandard +0.3 Part (a) is a standard first principles differentiation of a simple polynomial, which is routine but requires careful algebraic manipulation (5 marks reflects the working needed). Part (b) is straightforward application of power rule differentiation and substitution. Both are textbook exercises with no problem-solving required, making this slightly easier than average overall.
Spec1.07g Differentiation from first principles: for small positive integer powers of x1.07i Differentiate x^n: for rational n and sums

  1. Given that \(y = 2x^2 - 5x\), find \(\frac{dy}{dx}\) from first principles. [5]
  2. Given that \(y = \frac{16}{5}x^4 + \frac{48}{x}\), find the value of \(\frac{dy}{dx}\) when \(x = 16\). [3]

\begin{enumerate}[label=(\alph*)]
\item Given that $y = 2x^2 - 5x$, find $\frac{dy}{dx}$ from first principles. [5]

\item Given that $y = \frac{16}{5}x^4 + \frac{48}{x}$, find the value of $\frac{dy}{dx}$ when $x = 16$. [3]
\end{enumerate}

\hfill \mbox{\textit{WJEC Unit 1 2019 Q08 [8]}}