Question

найдите cos A, если: а) sin A=1/3, б) sin A = корень из 2/3

Answer 1

a)cos A =√1-sin²A=√1-(1/9)=√(9/9)-(1/9)=√(8/9)=(√8)/3=(2√2)/3

б)cos A =√1-sin²A=√1-(2/3)=√(3/3)-(2/3)=√(1/3)=1/√3=(√3)/3