Question

calculati lg(sin 40°) ⋅lg(sin 41°)⋅...⋅lg (sin 89°) ⋅lg(sin 90°)

Answer 1

Explicație pas cu pas:

$sin(90) = 1 \\ \\ lg(1) = \\ \\ = log_{10}(1) = \\ \\ = log_{10}( {10}^{0} ) = \\ \\ = 0$

Astfel [lg (sin 40°) ×....×lg(sin 89°) ] ×0 = 0