Prove the following:-
  1. If x = asecA + btanA and y = atanA + bsecA, prove that x2 - y2 = a2 - b2
  2. Whole Root 1 + cosA / 1 - cosA + Whole Root 1 - cosA / 1 + cosA = 2cosecA.

1) x = a secA+b tanA; y = atanA+bsecASo we have;L.H.S = x2-y2= a secA+b tanA2-atanA+bsecA2= a2sec2A+b2tan2A+2ab secA tanA-a2tan2A+b2sec2A+2ab secA tanA= a2sec2A+b2tan2A-a2tan2A-b2sec2A= a2sec2A-tan2A-b2sec2A-tan2A= a2-b2               {Since; sec2A-tan2A = 1}= R.H.S2) L.H.S =  1+cosA1-cosA+ 1-cosA1+cosA= 1+cosA1-cosA×1+cosA1+cosA+ 1-cosA1+cosA×1-cosA1-cosA= 1+cosA212-cos2A+1-cosA212-cos2A= 1+cosAsin2A+1-cosAsin2A= 1+cosAsinA+1-cosAsinA= 1+cosA+1-cosAsinA= 2sinA= 2cosecA= R.H.S

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