Question 830307
{{{2*cos(A)+sec(A)=3}}}
{{{2*cos(A)+1/cos(A)=3}}}
{{{2*cos(A)^2+1=3*cos(A)}}}
Let {{{u=cos(A)}}}
{{{2u^2-3u+1=0}}}
{{{(u-1)(2u-1)=0}}}
Two "u" solutions:
{{{u-1=0}}}
{{{u=1}}}
{{{cos(A)=1}}}
{{{highlight(A=0)}}}
and
{{{2u-1=0}}}
{{{2u=1}}}
{{{u=1/2}}}
{{{cos(A)=1/2}}}
Oops! I screwed up the previous solution. 
{{{highlight(A=60)}}} and {{{highlight(A=300)}}}
Three solutions.
Oops! I screwed up the previous solution. 
A can be 0, 60, and 300 degrees.