Tan A + Sec A - 1/ tan A + Sec A + 1
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((tan A+sec A)+1)/(tan A-sec A)-1) = (1+sin A) /cos A
Take the left hand side
[(sinA/cosA) + (1/cosA) + 1] / [(sinA/cosA) - (1/cosA) -1]
[((sinA+1)/cosA) + 1] / [(sinA-1)/cosA) -1]
[(sinA+1+cosA) / cosA] / [(sinA-1-cosA) / cosA]
(sinA+1+cosA) / (sinA-1-cosA)
Multiply both numerator and denominator by (sinA-1+cosA)
(sinA+1+cosA)(sinA-1+cosA) / (sinA-1-cosA)(sinA-1+cosA)
[(sinA+1)² - cos²A] / [(sinA-cosA)² -1]
(sin²A+2sinA+1-cos²A) / (sin²A-2sinAcosA+cos²A-1)
(sin²A+2sinA+1-(1-sin²A)) / (sin²A+cos²A-2sinAcosA-1)
(sin²A+2sinA+1-1+sin²A) / (sin²A+cos²A-2sinAcosA-1)
(2sin²A+2sinA) / (1-2sinAcosA-1)
2sinA(sinA+1) / 2sinAcosA <-- cancel out 2sinA
(1+sinA) / cosA
LHS=RHS so it is proven.
Identities used:
tanA = sinA/cosA
secA = 1/cosA
sin²A+cos²A = 1
Take the left hand side
[(sinA/cosA) + (1/cosA) + 1] / [(sinA/cosA) - (1/cosA) -1]
[((sinA+1)/cosA) + 1] / [(sinA-1)/cosA) -1]
[(sinA+1+cosA) / cosA] / [(sinA-1-cosA) / cosA]
(sinA+1+cosA) / (sinA-1-cosA)
Multiply both numerator and denominator by (sinA-1+cosA)
(sinA+1+cosA)(sinA-1+cosA) / (sinA-1-cosA)(sinA-1+cosA)
[(sinA+1)² - cos²A] / [(sinA-cosA)² -1]
(sin²A+2sinA+1-cos²A) / (sin²A-2sinAcosA+cos²A-1)
(sin²A+2sinA+1-(1-sin²A)) / (sin²A+cos²A-2sinAcosA-1)
(sin²A+2sinA+1-1+sin²A) / (sin²A+cos²A-2sinAcosA-1)
(2sin²A+2sinA) / (1-2sinAcosA-1)
2sinA(sinA+1) / 2sinAcosA <-- cancel out 2sinA
(1+sinA) / cosA
LHS=RHS so it is proven.
Identities used:
tanA = sinA/cosA
secA = 1/cosA
sin²A+cos²A = 1
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