Question

Please help me with this question

Answer 1

Dear student,

Sin 60 = root 3/2
So A= 60
Then
2 cot2 60-1 ( cot 60 = 1/ root 3)

2* 1/3 -1 = -1/3

I hope you will understand

Answer 2

Step-by-step explanation:

$sina = \frac{ \sqrt{3} }{2}$

$cos \: a = \sqrt{1 + ( { \frac{ \sqrt{3} }{2} )}^{2} }$

$cos \: a = \sqrt{1 + \frac{3}{4} }$

$cos \: a = \sqrt{ \frac{4 + 3}{4} }$

$cos \: a = \sqrt{ \frac{7}{4} }$

$cos \: a = \frac{ \sqrt{7} }{2}$

$2 {cot}^{2} a - 1$

$2 \frac{ {cos}^{2}a }{ {sin}^{2}a} - 1$

$2 \frac{ (\frac{ \sqrt{7} }{2}) }{ (\frac{ \sqrt{3} }{2}) } - 1$

$2 \frac{ \sqrt{7} }{2} \times \frac{2}{ \sqrt{3} } - 1$

$\frac{2 \sqrt{7} }{ \sqrt{3} } - 1$

$\frac{2 \sqrt{7 } - \sqrt{3} }{ \sqrt{3} } \times \frac{ \sqrt{3} }{ \sqrt{3} }$

$\frac{2 \sqrt{21} - 3}{3}$