Răspuns :
[tex]sin^{2}137+cos^{2}43=1\\
\\ sin^{2}(180-137)+cos^{2}43=1\\
\\ sin^{2}43+cos^{2}43=1\\
\\ 1=1~(A)\\
\\ sin~x=sin(180-x)\\
\\ \boxed{sin^{2}x+cos^{2}x=1}[/tex]
\\ sin^{2}(180-137)+cos^{2}43=1\\
\\ sin^{2}43+cos^{2}43=1\\
\\ 1=1~(A)\\
\\ sin~x=sin(180-x)\\
\\ \boxed{sin^{2}x+cos^{2}x=1}[/tex]