Salut!
1. Rezultatul calculului:
[tex][\frac{1}{2} :\frac{4}{12}+(-2)^3]:2^{-1} \\\\=[\frac{1}{2}*\frac{12}{4}+(-8)]:\frac{1}{2} \\\\=(\frac{3}{2}- \frac{8}{1} )*2\\\\=(\frac{3}{2}-\frac{16}{2} )*2\\\\=-\frac{13}{2}*\frac{2}{1}\\\\=-13[/tex]
2. Un patrat are diagonala 4√2 cm. Daca M este mijlocul lui AB, atunci aria triunghiului AMC este...cm².
Diagonala patrat=l√2
4√2=AB√2 |:√2
AB=4 cm
M-mijl AB⇒AM=MB=AB:2
AM=MB=4:2
AM=MB=2 cm
Formand ΔAMC, observam ca este obtuzunghic, deci inaltimea este exterioara, respectiv BC.
[tex]Aria_{AMC}=\frac{b*h}{2} =\frac{AM*BC}{2}=\frac{2*4}{2}=\frac{8}{2}=4cm^2[/tex]
Succes! ^-^
