Aplicamos a regra: $a+\frac{b}{c}$$=\frac{b+ac}{c}$, onde $a=\cos\left(2^kx\right)$, $b=\sin\left(2^kx\right)$, $c=2^k\sin\left(x\right)$, $a+b/c=\frac{\sin\left(2^kx\right)}{2^k\sin\left(x\right)}+\cos\left(2^kx\right)$ e $b/c=\frac{\sin\left(2^kx\right)}{2^k\sin\left(x\right)}$