Question 922267
{{{f(x)=sqrt(16-4x^2)}}} and {{{x=2sin(theta)}}}
{{{f(x)=sqrt(16-4*(2sin(theta))^2)}}}
{{{f(x)=sqrt(16-4*2^2*(sin(theta))^2)}}}
{{{f(x)=sqrt(16-4*4*(sin(theta))^2)}}}
{{{f(x)=sqrt(16-16*(sin(theta))^2)}}}
{{{f(x)=sqrt(16*(1-(sin(theta))^2))}}}
{{{f(x)=sqrt(16*(cos(theta))^2)}}}
{{{f(x)=sqrt(16)*sqrt(cos(theta))^2)}}}
{{{f(x)=4*abs(cos(theta)))}}}
and since {{{cos(theta)>0}}} for {{{0<theta<pi/2}}} ,
{{{f(x)=highlight(4cos(theta))}}}