Finding the variable A

Question

sect - 1/sect + 1 = A - cost/A + cost

Find A.

Answer 1

sec t-1/sect+1 = A-cos t/A+cost which could become( 1/cost-1)/1(1/cost+1) = A-cost/A+cost 

1/cost -1 =1-cost/cost and 1/cost+1=1+cost/cost ,devide 1-cost /cost by 1+cost/cost then it becomes 1-cost /1+cost 

 so when you equal 1-cost /1+cost with A-cost /A+cost very clear we find A=1