How do you differentiate #g(t)=4sect+tant#?

1 Answer
May 2, 2017

#g'(t)=4sect tant+sec^2t=sect(4tant+sect)#

Explanation:

The following trigonometric derivatives are very useful:

  • #d/dtsect=sect tant#
  • #d/dttant=sec^2t#

Thus,

#g'(t)=4sect tant+sec^2t=sect(4tant+sect)#


We can derive both of these derivatives:

#sect=(cost)^-1#

#d/dxsect=-(cost)^-2d/dtcost=(-1)/cos^2t(-sint)#

#=sect tant#

And:

#tant=sint/cost#

#d/dttant=((d/dtsint)cost-sint(d/dtcost))/cos^2t=(cos^2t+sin^2t)/cos^2t#

#=sec^2t#