" 9.If "cos theta=(cos alpha+cos beta)/(1+cos alpha cos beta)," then prove that one of values of "tan(theta)/(2)" is "tan(alpha)/(2)tan(beta)/(2)

If cos theta = (cos alpha - cos beta)/(1-cos alpha cos beta) , then one of the values of tan((theta)/(2)) is

If cos theta =(cos alpha - cos beta)/( 1- cos alpha cos beta), then one of the values of tan ((theta )/(2)) is

If cos theta=(cos alpha-cos beta)/(1-sin alpha sin beta), prove that one value of tan(theta)/(2)=(tan(alpha)/(2)-tan(beta)/(2))/(1-tan(alpha)/(2)-tan(beta)/(2))

If cos theta=(cos alpha cos beta)/(1-sin alpha sin beta), prove that one value of (tan)(theta)/(2)=((tan alpha)/(2)-(tan beta)/(2))/(1-tan(alpha)/(2)(tan beta)/(2))

If cos theta=(cos alpha cos beta)/(1-sin alpha sin beta), prove that one value of tan (theta/2)=(tan (alpha/2)-tan (beta/2))/(1-tan (alpha/2) tan (beta/2)).

If cos theta=(cos alpha-cos beta)/(1-cos alpha cos beta), prove that tan theta/2=+-tan alpha/2 cot beta/2.

If cos theta=(cos alpha-cos beta)/(1-cos alpha cos beta), prove that tan theta/2=+-tan alpha/2 cot beta/2.

If cos theta=(cos alpha-cos beta)/(1-cos alpha cos beta), prove that tan theta/2=+-tan alpha/2 cot beta/2.

If cos theta=(cos alpha cos beta)/(1-sin alpha sin beta), prove that one value of (tan) theta/2=(tan alpha/2-tan beta/2)/(1-t a n alpha/2 tan beta/2).