Answer:
Subtract 11 from both sides
Step-by-step explanation:
Answer:
B) irrational. Since an irrational number cannot equal a rational number.
The premise that c is rational is false
Step-by-step explanation:
The assumption that c is rational means that the difference c-a must be rational. That difference is b, so b=c-a would mean that b must be rational. But b is defined to be irrational. Since an irrational number cannot equal a rational number, a contradiction arises and the assumption that c is rational must be false. Therefore the sum (c) must be irrational. (B)
Recall the important identities:
i)

, the difference of squares formula.
ii)

, for any angle x.
Then,
from i)

then, from ii), we have

Answer: cos(theta)