Question

calcule o COS de X no triangulo da figuraa

Answer 1

(3R/2)² = R² + R² - 2.R.R.cos (x)
9R²/4 = 2R² - 2R².cos (x)
2R².cos (x) = 2R² - 9R²/4
8R².cos (x) = 8R² - 9R²
cos (x) = -R² / 8R²
cos (x) = -1/8

cos (x) = -0,125