cho tan alpha bằng 1/căn bậc hai của 3. tính cot alpha, sin alpha, cos alpha

`tan\alpha=1/\sqrt3`

Ta có:

`tan\alpha.cot\alpha=1`

`=>cot\alpha=1:tan\alpha=1:1/\sqrt3=\sqrt3`

Ta có: 

`1/(cos^2\alpha)=1+tan^2\alpha`

`=>1/(cos^2\alpha)=1+(1/\sqrt3)^2`

`=>1/(cos^2\alpha)=4/3`

`=>cos^2\alpha=3/4`

`=>cos\alpha=\sqrt3/2`

Ta có:

`sin^2\alpha+cos^2\alpha=1`

`=>sin^2\alpha=1-cos^2\alpha`

`=>sin^2\alpha=1-3/4`

`=>sin^2\alpha=1/4`

`=>sin\alpha=1/2`

Vậy: 

`sin\alpha=1/2`

`cos\alpha=\sqrt3/2`

`cot\alpha=\sqrt3`