Question #2b836

1 Answer
Nov 23, 2017

Please see below.

Explanation:

#(secx+tanx)cosx-1=sinx#

#secx=1/cosx#

and #tanx=sinx/cosx#

Let's plug them in:

#(1/cosx+sinx/cosx)cosx-1=sinx#

#(cosx/cosx+(sinxcosx)/cosx)-1=sinx#

#1+sinx-1=sinx#

#sinx=sinx#

So, this equation holds true for all values of #x#.

But we can do it also by plugging in #pi/3# for #x#:

#(sec(pi/3)+tan(pi/3))cos(pi/3)-1=sin(pi/3)#

#(2+sqrt3)(1/2)-1=sqrt3/2#

#1+sqrt3/2-1=sqrt3/2#

#sqrt3/2=sqrt3/2#