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find the exact value of cos2a

0 votes
tan a=-3/2 and a is in quadrant iv
asked May 16, 2016 in TRIGONOMETRY by anonymous
reshown May 16, 2016 by goushi

2 Answers

0 votes

Step 1:

The trigonometric expression is .

Here, in the fourth quadrant.

Rewrite the trigonometric equation is

Double angle formula for trigonometric: .

Substitute image in the above formula.

image

Half angle formula for trigonometric: image.

image

Solution:

The value of image.

answered May 16, 2016 by Anney Mentor
0 votes
Quadrant information is redundant

 

as  cos2A=(1-tan²A)/(1+tan²A)
answered Jul 5, 2016 by lab.bhattacharjee Rookie

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