Question

sin a,tg a,ctg a,если cos a=-0,8, П/2

Answer 1

Известен cos(a)
$sin^{2}(a)+cos^{2}(a) = 1 \ sin(a) = sqrt{1-cos^{2}(a)} \ tg(a) = frac{sin(a)}{cos(a)} \ ctg(a) = frac{1}{tg(a)}$
$cos(a) = -0.8 \ sin(a) = frac{+}{} 0.6\ tg(a) = frac{+}{} 0.75\ ctg(a) = frac{+}{} frac{4}{3}$
$cos(a) = frac{ pi }{2} \ sin(a) = frac{+}{} sqrt{1- frac{pi^{2}}{4} } \ tg(a) = frac{+}{} frac{ sqrt{1- frac{pi^{2}}{4} } }{frac{pi}{2}}\ ctg(a) = frac{+}{} frac{ frac{pi}{2}}{ sqrt{1- frac{pi^{2}}{4} }}$