Identify Expression: Identify the expression on the left side of the equation.Simplify cscA=1/sinA.Substitute into the left side: (cscA−1)/(cscA+1)=(1/sinA−1)/(1/sinA+1).
Simplify Left Side: Simplify the expression by finding a common denominator.Rewrite as (1−sinA)/(1+sinA).
Find Common Denominator: Identify the expression on the right side of the equation.Rewrite cosA/(1+sinA) and then square it: (cosA/(1+sinA))2.
Rewrite Right Side: Use the Pythagorean identity sin2A+cos2A=1 to express cos2A.Substitute cos2A=1−sin2A into the squared term: (cosA/(1+sinA))2=((1−sin2A)/(1+sinA))2.
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