Question

(cos^(2)9^(0)+cos^(2)81^(0))/(sin^(2)52^(0)+sin^(2)38^(0))
найти значение выражения.

Answer 1

$\displaystyle\bf\\\frac{Cos^{2} 9^\circ+Cos^{2}81^\circ }{Sin^{2} 52^\circ+Sin^{2}38^\circ } =\frac{Cos^{2} 9^\circ+Cos^{2}(90^\circ-9^\circ) }{Sin^{2} (90^\circ-38^\circ)+Sin^{2}38^\circ } =\\\\\\=\frac{Cos^{2} 9^\circ+Sin^{2}9^\circ }{Cos^{2} 38^\circ+Sin^{2}38^\circ } =\frac{1}{1} =1$