Răspuns:
1.
cosC=AC/BC=6/10=3/5
2.
BC=10
sinB=3/5
AB/BC=3/5
AB/10=3/5
5AB=30
AB=30:5=6
Teorema lui Pitagora
BC²=AB²+AC²
10²=6²+AC²
AC²=100-36=64
AC²=8²
AC=8
P=AB+BC+CA
P=6+10+8
P=24
3.
sinB+cosB=sinC+cos
AC/BC+AB/BC=AB/BC+AC/BC
asevărat
adunarea este comutativă
4.
sinB=2/3
sin²B+cos²B=1
4/9+cos²B=1
cos²B=1-4/9
9cos²B=9-4
9cos²B=5
cos²B=5/9
5.
sin60⁰=2×sin30⁰×cos30⁰×tg30⁰×ctg30⁰
√3/2=2×1/2×√3/2×√3/3×√3
√3/2=1×√3/2×√3/3×√3
√3/2=√3/2×√3/3×√3
√3/2=3/6×√3
√3/2=1/2×√3
√3/2=√3/2
adevărat
