Y^2=4-x^2 determine whether the equation defines y as a function of x

Yes , taking root on both sides we have y = √(4-x^2) so y is dependant on x and x only..so y is a function of x .

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐