Let f(x) = 3x^4 + 4x^3 - 12x^2 - 24x + 5, x E R ( element of all real numbers)
f'(x) = 12x^3 + 12x^2 - 24x - 24
Let f'(x) = 0
12x^3 + 12x^2 - 24x - 24 = 0
12[(x+1)(x^2-2)]=0
therefore x=-1 or x=sqrrt2 or x= -sqrrt 2
Here's when i am having trouble.
How do i pick an appropriate start and end point?
I constructed a table:
(x) -2 | -1| √1 | √2
f’(x) -24| 0| -24 | 0
Why am i getting incorrect values, shouldn't the point before -1 give me a positive tangent instead of a negative one?
Edit: Solved, thanks anyway.