Question

lf cos A=12/13then find value of tan 2A.
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Answer 1

Answer:

Step-by-step explanation:

Given that,

cos A = 12 / 13 = BC / AC ( ∵In right triangle ABC )

By using Pythagoras theorem,

AC² = AB² + BC²

( 13 )² = AB² + ( 12 )²

169 = AB² + 144

AB² = 169 - 144 = 25

AB = √ 25

AB = 5

tan A = AB / BC = 5 / 12.

∴ tan 2A = 2 tan A / ( 1 - tan² A )

= 2 ( 5/12 ) / [ 1 - ( 5/12)² ]

= ( 5/6 ) / [ 1 - 25 / 144 ]

= ( 5/6 ) / [ ( 144 - 25 ) / 144 ]

= ( 5/6 ) / ( 119 / 144 )

= ( 5/6 ) × ( 144/119 )

= ( 5 × 144 ) / ( 6 × 119 )

= 360 / 357

Answer 2

Step-by-step explanation:

Step-by-step explanation:•° Given :-

• Step-by-step explanation:•° Given :-cos A = 12/13

Step-by-step explanation:•° Given :-cos A = 12/13 •° To find :-

• Step-by-step explanation:•° Given :-cos A = 12/13 •° To find :-Value of 2 A

Step-by-step explanation:•° Given :-cos A = 12/13 •° To find :-Value of 2 A •° Solution :-

2 A = 2 tan A / ( 1 - tan² A )

= 360/357