1.
lim⁡x→08sin⁡8x{1−cos⁡(x2/2)−cos⁡(x2/4)+cos⁡(x2/2)cos⁡(x2/4)}\displaystyle\lim_{x\to0}\frac{8}{\sin^8x}\{1-\cos(x^2/2)-\cos(x^2/4)+\cos(x^2/2)\cos(x^2/4)\}