Cards In This Deck

• $$\begin{gathered} \text{Which of these lines are parallel?} \\ \text{L1: }y=2x+1 \\ \text{L2: }2y=4x-6 \\ \text{L3: }y+2x=5 \end{gathered}$$
  $\text{L1 and L2 are parallel.}$
• $\text{Condition for two non-vertical lines with gradients }{m}_1\text{ and }{m}_2\text{ to be perpendicular?}$
  $m_1\times m_2=-1$
• $$\begin{gathered} \text{True or False?} \\ \text{A line perpendicular to }y=5\text{ has a gradient of }-5\text{.} \end{gathered}$$
  $$\begin{gathered} \text{False} \\ \text{Correct Answer: The line is vertical (}x=k\text{) and its gradient is undefined.} \end{gathered}$$
• $\text{Under what condition are two lines (such as a tangent and a normal) considered perpendicular?}$
  $$\begin{gathered} \text{If the product of their gradients is }-1\text{.} \\ {m}_1\times m_2=-1 \\ \text{(Unless one is vertical and the other horizontal).} \end{gathered}$$