\frac{1 - \cos x}{x \cdot x}\begin{array}{l}
\mathbf{if}\;x \le -0.03422954134275022625155671107677335385233 \lor \neg \left(x \le 0.03575238836244829659927191300994309131056\right):\\
\;\;\;\;\frac{\sqrt{\log \left(e^{1 - \cos x}\right)} \cdot \left|\sqrt[3]{1 - \cos x}\right|}{x} \cdot \frac{\sqrt{\sqrt[3]{\frac{{1}^{3} - {\left(\cos x\right)}^{3}}{\cos x \cdot \left(\cos x + 1\right) + 1 \cdot 1}}}}{x}\\
\mathbf{else}:\\
\;\;\;\;\left(\frac{1}{720} \cdot {x}^{4} + \frac{1}{2}\right) - \frac{1}{24} \cdot {x}^{2}\\
\end{array}double f(double x) {
double r25569 = 1.0;
double r25570 = x;
double r25571 = cos(r25570);
double r25572 = r25569 - r25571;
double r25573 = r25570 * r25570;
double r25574 = r25572 / r25573;
return r25574;
}
double f(double x) {
double r25575 = x;
double r25576 = -0.034229541342750226;
bool r25577 = r25575 <= r25576;
double r25578 = 0.0357523883624483;
bool r25579 = r25575 <= r25578;
double r25580 = !r25579;
bool r25581 = r25577 || r25580;
double r25582 = 1.0;
double r25583 = cos(r25575);
double r25584 = r25582 - r25583;
double r25585 = exp(r25584);
double r25586 = log(r25585);
double r25587 = sqrt(r25586);
double r25588 = cbrt(r25584);
double r25589 = fabs(r25588);
double r25590 = r25587 * r25589;
double r25591 = r25590 / r25575;
double r25592 = 3.0;
double r25593 = pow(r25582, r25592);
double r25594 = pow(r25583, r25592);
double r25595 = r25593 - r25594;
double r25596 = r25583 + r25582;
double r25597 = r25583 * r25596;
double r25598 = r25582 * r25582;
double r25599 = r25597 + r25598;
double r25600 = r25595 / r25599;
double r25601 = cbrt(r25600);
double r25602 = sqrt(r25601);
double r25603 = r25602 / r25575;
double r25604 = r25591 * r25603;
double r25605 = 0.001388888888888889;
double r25606 = 4.0;
double r25607 = pow(r25575, r25606);
double r25608 = r25605 * r25607;
double r25609 = 0.5;
double r25610 = r25608 + r25609;
double r25611 = 0.041666666666666664;
double r25612 = 2.0;
double r25613 = pow(r25575, r25612);
double r25614 = r25611 * r25613;
double r25615 = r25610 - r25614;
double r25616 = r25581 ? r25604 : r25615;
return r25616;
}



Bits error versus x
Results
if x < -0.034229541342750226 or 0.0357523883624483 < x Initial program 1.1
rmApplied add-sqr-sqrt1.3
Applied times-frac0.6
rmApplied *-un-lft-identity0.6
Applied add-cube-cbrt0.7
Applied sqrt-prod0.7
Applied times-frac0.7
Applied associate-*r*0.7
Simplified0.7
rmApplied add-log-exp0.7
Applied add-log-exp0.7
Applied diff-log0.8
Simplified0.7
rmApplied flip3--0.7
Simplified0.7
if -0.034229541342750226 < x < 0.0357523883624483Initial program 62.1
Taylor expanded around 0 0.0
Final simplification0.4
herbie shell --seed 2019352
(FPCore (x)
:name "cos2 (problem 3.4.1)"
:precision binary64
(/ (- 1 (cos x)) (* x x)))