Question

1-sin2A/1+sin2A=(cotA-1/cotA+1)^2​

Answer 1

Step-by-step explanation:

(1-sin2A)/(1+sin2A)=(1-2sinAcosA)/(1+2sinAcosA);

divide through by cos^2A:

(sec^2A-2tanA)/(sec^2A+2tanA);

substitute 1+tan^2A for sec^2A:

(1-2tanA+tan^2A)/(1+2tanA+tan^2A)=((1-tanA)/(1+tanA))^2;

so, sqrt((1-sin2A)/(1+sin2A))=(1-tanA)/(1+tanA).