Answer:
[tex]y = 1 - \frac{2}{49}\cdot x^{2}[/tex]
Step-by-step explanation:
The parametrical components of the curve are:
[tex]x = 7 \cdot \sin \theta[/tex] and [tex]y = \cos 2\theta[/tex]
After some trigonometrical and algebraic handling, the parametrical variable is eliminated in the resulting expression:
[tex]y = \cos^{2}\theta - \sin ^{2}\theta[/tex]
[tex]y = 1 - 2\cdot \sin^{2}\theta[/tex]
[tex]y = 1 - 2\cdot \left(\frac{x^{2}}{49} \right)[/tex]
[tex]y = 1 - \frac{2}{49}\cdot x^{2}[/tex]