Răspuns:
Explicație pas cu pas:
x∈cadran III sinx=-5/12
cosx=√1-sin²x=-√1-25/144=-√(144-25)/144=-√119/12
tgx/2=2tgx/(1-tg²x)=2sinx/cosx/(cos²x-sin²x)/cos²x=2sinxcos/(1-2sin²n)=
=sin 2x/(1-2sin²x)
tgx/2=2(-5/12)(-√119)/12/(1-2×25/144)=10√119/(144-50)=10√119/94=5√119/47
