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Which of the following is/are not correct? (more than one correct) a) tan(x+y) = tan x + tan y/1-tan x .tan y b) cos 2x = cos 2 x – sin 2 x c) sin 2x = 2 tan x/ 1-tan2x d) cos 3x = 4cos 3 x + 3cosx



Which of the following is/are not correct? (more than one
correct)



a)   
tan(x+y)
= tan x + tan y/1-tan x .tan y



b)   
cos
2x = cos2x – sin2x



c)    
sin
2x = 2 tan x/ 1-tan2x



d)   
cos
3x = 4cos3x + 3cosx



Grade:9

3 Answers

Aman Bansal
592 Points
11 years ago

Dear Anushka

A,B,C are correct.

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Panga Mahita
37 Points
11 years ago

sin2x= 2tanx/1+tan2x          and cos3x = 4cos3x - 3cos x         

so c, d are incorrect answers

If understood then plz approve my answer.

ayan shanky
19 Points
11 years ago

answer  c,d

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