2.2 Lösning 2b
Från Mathonline
\( f(2) = -3\cdot 2^2 + 2\cdot 2 - 12 = -3\cdot 4 + 4 - 12 = -12 + 4 - 12 = -20 \)
\( f(-2) = -3\cdot (-2)^2 + 2\cdot (-2) - 12 = -3\cdot 4 - 4 - 12 = -28 \)
\( {\Delta y \over \Delta x} = {f(2)\,-\,f(-2) \over 2\,-\,(-2)} = {-20\,-\,(-28) \over 4} = {8 \over 4} \) \( = \, 2 \)
