Question

tan A=b/a find the value of cos2A

Answer 1

Answer:

I am not understanding what is the question

Answer 2

$tan = \frac{ perpendicular}{base}$

$tan \: a = \frac{b}{a}$

$perpendicular = b \: and \: base = a$

$hypotenuse^{2} = perpendicular^{2} + base^{2}$

$hypotenuse = \sqrt{ {perpendicular}^{2} + {base}^{2}}$

here, hypotenuse =$\sqrt{ {b}^{2} + {a}^{2}}$

$cos = \frac{base}{hypotenuse}$

$cos \: a = \frac{a}{ \sqrt{ {b}^{2} + {a}^{2} } }$

$cos \: 2a = \frac{2a}{ \sqrt{ {b}^{2} + {a}^{2} } }$

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