Question

find the equation of a line tangent to g(x)=4x*sin(2x) at x=pi/8

Answer 1

slope of g(x) at x=pi/8 is given by the derivative at the point x=pi/8.
At x=pi/8, derivative of g(x) is
4sin(2x)+8xcos(2x) = (4+pi)/(2^1/2)
Slope of the tangent is this.
Now, it passes through the point (pi/8,pi/(2*2^1/2))
(y-(pi/2*2^1/2))/(x-pi/8)=(4+pi)/(2^1/2)

Answer 2

oh so u use product rule...i was using chain rule and gettin all confused lol. thanks =)

Answer 3

Yes product rule. :)