numerical methods – Find the upper bound of the error for the approximation of \$int_{x_1}^{x_2}cos(x)\$

Consider $$f(x) = cos(x)$$ and the points $$x_0 = pi/2$$, $$x_1 = pi/4$$
and $$x_2=3pi/4$$. Consider $$f(x_i)$$ with 5 decimal places. Find an
estimate for the error of integration when you use Simpson’s rule to
calculate the integral of f between $$x_1$$ and $$x_2$$.

I did

$$E(f) < |frac{b-a}{180}||frac{b-a}{N}|max_{(x_1,x_2)} |f^{(4)}| = 0.0023479$$

Is this correct?

Is the reason I am given 3 points that I need an even number of intervals to use Simpsons rule and is that why I set N = 2 and not 1?