Question

Tan (pi/4 + x) = 1 + tan x/1 - tanx

Answer 1

Prove:
tan ( π / 4 + x ) = ( 1 + tanx ) / ( 1 - tanx )

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SOLVE L.H.S :
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use formula:

tan ( A + B )

=( tanA + tanB ) /( 1 - tanA tanB )

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tan ( π /4 + x )

= (tan π/4 + tanx )/ (1 - tan π/4 tanx)

= (tan180 /4 + tanx )/ ( 1 - tan180/4 tanx )

= (tan45° + tan x )/ (1 - tan45° tanx)

= 1 + tanx / 1 - ( 1) tanx

= 1 + tanx / 1 - tanx = R.H.S

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L.H.S = R.H.S , hence proved.
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