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ITMC 2018 Grade 11 National Preliminary set01 Question 7

ITMC · ITMC 2018 Grade 11 National Preliminary set01

Question 7

In triangle $ABC$, $\cos A=5/13$ and $\cos B=3/5$. Find $\cos C$.
  1. $-\frac{63}{65}$
  2. $-\frac{33}{65}$
  3. $1$
  4. $\frac{33}{65}$
  5. $\frac{63}{65}$