JuliaB

I think you have trouble solving this because you didn't simplify second derivative correctly after you set it equal to zero. Is (1+cos^2(x))^2 a denominator only for 2x or for the whole expression (x^2-4)*(sin(2x)-2x(1+cos^2(x)? If it's a denominator for...

Steeve you are right - I shouldn't have set denominator to zero but not because of your reasoning. No. But because it's a second derivative. When it comes to first derivative you CAN set (and have to sometimes) denominator to zero if you want to find vert...

First find the slope m=(y2-y1)/(x2-x1) you can simply plug in your points A(x1, y1)and B(x2, y2) in to the formula m=(8-(-4))/(11-3) Then use point-slope form to get an equation for the line (y - y1) = m (x - x1) You can use either point A or B for this f...