a$.$ Find the equation of the line tangent to the following curve at the given value of $x.$

b$.$ Use a graphing utility to plot the curve and the tangent line.

$y=4sinxcosx$;$x=\frac{}{4}$

a$.$ Find the equation of the line tangent to the given curve at the given value of $x.$

$y=$

$($Type an exact answer, using $$ as needed.$)$

b$.$ Select the correct graph of the curve and the tangent line below.

A$.$

B$.$

All graphs shown in a $-2,2$ by $-10,10$ viewing window.

c$.$

D$.$