ddxtanx=\dfrac{d}{dx}\tan x =dxdtanx=A−cotx-\cot x−cotxBsec2x\sec^2 xsec2xcheck_circleCsecx\sec xsecxDcotx\cot xcotxExplanationtan=sin/cos\tan = \sin/\costan=sin/cos; quotient rule gives sec2x\sec^2 xsec2x.