Question 1036034
.
If cos0=1/4 what is the value os in 0? Assume that 0 is an angle in the first quadrant
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


The formulation has typos.
Let me reformulate (and solve) it as it should be.


<pre>
--------------------------------------------
   If  {{{cos(theta)}}} = {{{1/4}}}  what is the value of {{{sin(theta)}}} ?

   Assume that {{{theta}}} is an angle in the first quadrant.
--------------------------------------------


<U>Solution</U>

If  {{{cos(theta)}}} = {{{1/4}}}  then  {{{sin(theta)}}} =  {{{sqrt(1 - cos^2(theta))}}} = {{{sqrt(1 - (1/4)^2)}}} = {{{sqrt(1 - 1/16)}}} = {{{sqrt((16-1)/16)}}} = {{{sqrt(15/16)}}} = {{{sqrt(15)/4}}}.

The sign  "+"  was chosen at the square root because the sine is positive for an angle at the first quadrant. 
</pre>