Step-by-step explanation:
note that
sin²x = (1-cos²x)
LHS= cos²x - 2 sin²x
= cos²x - 2(1-cos²x)
= cos²x - 2 + 2cos²x
= 3cos²x - 2
or
cos²x = (1-sin²x)
LHS= cos²x - 2 sin²x
=1-sin²x - 2 sin²x
= 1-3sin²x
Answer:
No real solutions.
Step-by-step explanation:
729s^-5 = 729/s^5
729/s^5 = 3^2(1-s) = 9(1-s)
729=9(1-s)(s^5)
(1-s)(s^5)=81
s^5-s^6=81
Because 81 > 0 this means s^6 must be less than s^5. This is never possible as 6 is even so is always positive and is always greater in magnitude than s^5. The only time this isnt the case is when s is a decimal less than 1, but then the difference would be also less than 1 and not 81.
Answer:
Refractive index of a medium depends upon the refractive index of the surroundings
Answer:
Step-by-step explanation:
My answered came at B I’m not sure though but I hope it is correct!!
