Find ddx[sec3x]\frac{d}{dx}[\sec^3 x]dxd[sec3x].
3sec3xtanx3\sec^3 x \tan x3sec3xtanx
3sec2xtanx3\sec^2 x \tan x3sec2xtanx
3sec2x3\sec^2 x3sec2x
3sec3x3\sec^3 x3sec3x