Question 957695
Take the derivative and set it equal to zero,
{{{dy/dx=-4sin(4x)+8sin(2x)=0}}}
Solutions are when {{{x=n*pi}}} and {{{x=n*(pi/2)}}}
Then,
When {{{x=n*pi}}}
{{{y[min]=1-4+3=0}}}
When {{{x=n*(pi/2)}}}
{{{y[max]=1+4+3=8}}}