Question 1139162
<pre>
{{{sqrt((1+cos(14^"o"))/2)}}}

That looks like the right side of the identity:

{{{cos(alpha/2)=""+-sqrt( (1+cos(alpha))/2)}}}

So we substitute 14° for <font face="symbol"><b>a</b></font> using the + sign:

{{{cos(14^"o"/2)=sqrt( (1+cos(14^"o"))/2)}}}

{{{cos(7^"o")=sqrt( (1+cos(14^"o"))/2)}}}

Answer: {{{cos(7^"o")}}}

Edwin</pre>