1=7tgx=>tgx=\frac{1}{7} " alt=" cosx=7sinx\\ =>1=7tgx=>tgx=\frac{1}{7} " align="absmiddle" class="latex-formula">
\frac{1}{2}sin2x=\frac{1}{2}*\frac{2tgx}{1+tg^2x}=\\ \frac{1}{2}*\frac{2*\frac{1}{7}}{1+\frac{1}{49}}=\frac{7}{50}=\frac{14}{100}=0.14 " alt=" => \frac{1}{2}sin2x=\frac{1}{2}*\frac{2tgx}{1+tg^2x}=\\ \frac{1}{2}*\frac{2*\frac{1}{7}}{1+\frac{1}{49}}=\frac{7}{50}=\frac{14}{100}=0.14 " align="absmiddle" class="latex-formula">