Given △ABC ~ △XYZ, what is the value of cos(Z)? Five-thirteenths Five-twelfths Twelve-thirteenths Twelve-fifths

Find the gradient of f(x, y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

Find the solutions for a triangle with a =16, c =12, and b = 63º

What is the base of 1/9 to the power of 2