Question

Cпростите вираз дуже срочно треба
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Answer 1

$({{sin}\frac{5\pi}{2} {cos}a + cos \frac{5\pi}{2} sina})^{2} \\ = ({sin(2\pi + \frac{\pi}{2} )cosa + cos(2\pi + \frac{\pi}{2} )sina }) ^{2} \\ = ({1 \times cosa + 0 \times sina} )^{2} \\ = {cos}^{2} a$