Question

If y=(1-tanx)/(1+tanx) find dy/dx

Answer 1

$y=(1-tanx)/(1+tanx)$
$dy/dx=sec^x(1-tanx)-(1+tanx)(-sec^x)/(1-tanx) (quotient rule)$
$dy/dx=sec^x-sec^xtanx+sec^x+sec^xtanx/(1-tanx)$
$dy/dx=2sec^x/(1-tanx)$

Answer 2

ans is 2(secx / (1 -tex)