Problem

Problem

If xcos⁡α+ysin⁡α=xcos⁡β+ysin⁡β=2ax \cos \alpha + y \sin \alpha = x \cos \beta + y \sin \beta = 2a (0<α,β<π2)\left(0 < \alpha, \beta < \frac{\pi}{2}\right), then a. cos⁡α+cos⁡β=4axx2+y2\cos \alpha + \cos \beta = \frac{4ax}{x^2 + y^2} b. cos⁡αcos⁡β=4a2−y2x2+y2\cos \alpha \cos \beta = \frac{4a^2 - y^2}{x^2 + y^2} c. sin⁡α+sin⁡β=4ayx2+y2\sin \alpha + \sin \beta = \frac{4ay}{x^2 + y^2} d. sin⁡αsin⁡β=4a2−x2x2+y2\sin \alpha \sin \beta = \frac{4a^2 - x^2}{x^2 + y^2}

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