Question

Tính giá trị biểu thức sau:

a) \(A = \frac{{\sin {{30}^o}.\cos {{30}^o}}}{{\cot {{45}^o}}}\)

b) \(B = \frac{{\tan {{30}^o}}}{{\cos {{45}^o}.\cos {{60}^o}}}\) 

Answer 1

a) \(A = \frac{{\sin {{30}^o}.\cos {{30}^o}}}{{\cot {{45}^o}}} = \frac{{\frac{1}{2}.\frac{{\sqrt 3 }}{2}}}{1} = \frac{{\sqrt 3 }}{4} \approx 0,43\)

b) \(B = \frac{{\tan {{30}^o}}}{{\cos {{45}^o}.\cos {{60}^o}}} = \frac{{\frac{{\sqrt 3 }}{3}}}{{\frac{{\sqrt 2 }}{2}.\frac{1}{2}}} = \frac{{2\sqrt 6 }}{3} \approx 1,63\)