1 = \frac{a^{2/3}}{a^{2/3}}\cdot cos^2(t) + \frac{a^{2/3}}{a^{2/3}}\cdot sin^2(t) = \frac{a^{2/3}}{a^{2/3}}\cdot ( cos^3(t) )^{2/3} + \frac{a^{2/3}}{a^{2/3}}\cdot ( sin^3(t) )^{2/3}