[cos^(-1)x+cos^(-1)y+cos^(-1)z,=pivec u|" fues "(1)/(cos)|f_(v)|_(zeta)],[,x^(2)+y^(2)+z^(2)+2xyz=1]

If cos^(-1)x+cos^(-1)y+cos^(-1)z=pi then

If cos^(-1)x+cos^(-1)y+cos^(-1)z=pi , then

If cos^(-1)x+cos^(-1)y+cos^(-1)z=pi , then

If cos^(-1)x+cos^(-1)y+cos^(-1)z=pi , then

If cos^(-1) x + cos^(-1) y + cos^(-1) z = pi , then

If cos^(-1)x +cos^(-1)y +cos^(-1)z =3pi then x+y+z is :

If cos^(-1) x + cos^(-1) y + cos^(-1) z = pi" , prove that " x^(2) + y^(2)+ z^(2) + 2xyz = 1 .

If (i) cos^(-1) x + cos^(-1) y + cos^(-1) z = pi , prove that : x^(2) +y^(2) +z^(2) + 2xyz = 1 (ii) If sin^(-1) x + sin^(-1) y + sin^(-1) z = pi/2 , prove that : x^(2) +y^(2) +z^(2) +2xyz = 1

If cos^(-1) x + cos^(-1) y + cos ^(-1) z = pi and 0 lt x,y,z lt 1 show that x^(2) +y^(2) +z^(2) +2xyz = 1