Question

in reperul cartezian xOy se considera punctele A(4,0) B(0,2) C(1,-1) D(2,m). m apartine lui R calculati aria ∆ABC

Answer 1

$A= \frac{1}{2} *|delta|$

delta=[tex] \left[\begin{array}{ccc}1&1&1\\4&0&1\\0&2&-1\end{array}\right]= 0+0+8-(0+2-4)=8-2+4=6+4=10 [/tex]

$A= \frac{1}{2}*|10|= \frac{10}{2}=5$