1
Boundary Line Conventions
The boundary line $y = mx + c$ divides the plane into two half-planes:
Solid Line (Garis Padu): For $\le$ or $\ge$. Points on the line are included in solution.
Dashed Line (Garis Sempang): For $<$ or $>$. Points on the line are NOT included.
2
The Origin Test Point $(0, 0)$
To determine which side of the line to shade:
Substitute $(0, 0)$ into inequality:
If TRUE $\implies$ shade the region containing $(0, 0)$.
If FALSE $\implies$ shade the opposite region!
3
Mathematical Modeling
Translating everyday constraints into inequalities:
- "At most / tidak melebihi": $\le$
- "At least / sekurang-kurangnya": $\ge$
- "More than / lebih daripada": $>$
- "Less than / kurang daripada": $<$
SPM Shading Traps: Clean Shading & Line Types
In SPM Paper 2, drawing a solid line when a dashed line was required automatically causes you to lose the boundary line mark! Ensure your pencil shading covers only the feasible region common to ALL stated inequalities.