Question

Cos4Q-cos2Q=Sin4Q-sin2Q it is from trigonometry class 10

Answer 1

Answer:

sin Q + sin2Q = 1

---> sin Q = 1 - sin2Q

---> sin Q = cos2Q   [as, 1 - sin2Q = cos2Q] .... (I)  

So,

cos2Q + cos4Q  

= cos2Q + (cos2Q)2   [as, cos4Q = (cos2Q)2]

= sin Q + (sin Q)2  [from (I)]

= sin Q + sin2Q

= 1 .... (ans) ....

Hope this helps !!