Question

Cos3a when tana=5/12

Answer 1

Answer:

Tan A = perpendicular/base

Cos A = Base /hypotenuse

Perpendicular =5x

base=12x

By Pythagoras theorem

H^2=B^2+p^2

H^2=144x^2+25x^2

h^2=169x^2

h=13x

Cos a=12/13

Cos 3a=3×12/13

36/13

Step-by-step explanation:

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