Answers

2014-11-05T23:49:58+05:30
1)cos2Ф=cos60=1/2
2)1-tan²30/1+tan30
 =(1-1/3)/(1+1/3)
=2/3*3/4
=1/2
3)R.H.S=1-tan²2Ф/1+tan²2Ф
BYE PYTHAGORAS IDENTITY.....1+tan²α=sec²α=1/cos²α
R.H.S=1-tan²2Ф/(1/cos²2Ф)
           =COS²2Ф-SIN²2Ф
               =cos2Ф....proved
(NOTE:-In ans(3),i have skipped some steps...try to understand them...if not,tell me i will tell u again)



          
 


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