*cos4 x – sin4x is also equal to _______.
a. 1 + 2cos2x
b. 1 - 2cos2x
c. 1 + 2sin2x
d.1 - 2sin2x
hint: cos2x + sin2x = 1
5
4
3
2
1
Times up!!!
Well if you answered letter ‘d’ you are right!!!
Solution:
cos4 x – sin4x
(cos2x + sin2x) (cos2x - sin2x)
( 1 ) (1- sin2x - sin2x)
1 - 2 sin2x
It is so easy! Am I right? Hope you got it right!
It is so easy! Am I right? Hope you got it right!
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