\f12 Let sin A = - 13 with A in QIV and find cos (2A) = Preview TIP Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 243, 5+4) Enter DNE for Does Not Exist, oo for Infinity Get Help: Video\f2 Let cos A = with A in QIV and find V13 cos (2.A) = Preview TIP Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 243, 5+4) Enter DNE for Does Not Exist, oo for Infinity Get Help: Video