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2014-06-14T21:15:32+03:00
SinB=AC/BC
BC²=AB²+AC²
BC²=144+25
BC²=169
BC=13
sinB=12/13
sinC=AB/BC
sinC=5/13
cosB=AB/BC=5/13
tgC=AB/AC
tgC=5/12
ctgB=AB/AC
ctgB=5/12
sin²B+cos²B=(12/13)²+(5/13)²=(144+25)/169=169+169=1
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2014-06-14T21:21:32+03:00
Ducem AD inaltimea triunghiului ABC
ABD triunghi dreptunghic
cos B=BD/AB
BD=ABcosB
BD=3√2*√2/2=3⇒DC=1
sinB=AD/AB⇒AD=AB sinB=3√2*√2/2=3
ΔADC triunghi dreptunghic se aplica t lui Pitagora
AC²=AD²+DC²
AC²=9+1⇒AC=√10
PABC=3√2+√10+4