Question

prove question number 7 ​

Answer 1

hope its helpful ^_^

Answer 2

Answer:

Step-by-step explanation:

Recall that

        cot α = 1 / tan α

so

        ( cot α ) × ( tan α ) = 1

So we just need to multiply the numerator and denominator in LHS expression by tan α :

$\displaystyle\frac{\cot\alpha-1}{\cot\alpha+1}=\frac{(\cot\alpha-1)\times\tan\alpha}{(\cot\alpha+1)\times\tan\alpha}=\frac{1-\tan\alpha}{1+\tan\alpha}$