Question

if cos A=2/5, find the value of 4+4 tan square A
( 1 mark answer )


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Answer 1

given cosA = 2/5

side of adjacent to angle A / hypotenuse

AB/AC= 2/5

let AB = 2x

AC = 5x

using Pythagoras theorem to find BC

( hypotenuse)²= (height)²+(base)²

AC² = AB²+BC²

see the continue part in the picture

remaining continue

thus 4+tan²A

4+4(✓21/2)²

4+4*21/4

4+21

25