Cot=cos\sin
sec=1\cos
cosx\sinx÷1\cosx=
cos^2x\sinx=1-sin^2x\sinx=
1\sinx-sin^2x\sinx= 1/sinx-sinx
Answer: C: 12-7x
Step-by-step explanation:
This expression is a good example of the difference of two squares, as 144 is the square of 12, while 49x² is the square of 7x.
Any difference of two squares 
can be factored into the sum of their square roots times the difference of their square roots 
.
Let's factor our expression.
Out of all the options given, only 
is a factor. Hence, option C is correct.
Answer:
be rewritten as a square of a sum
Step-by-step explanation:
The next step of your proof is to subtract (a/b) from both sides.
Then you get, x = (m/n) - (a/b)
Since rationals are closed over addition, (m/n) + (-a/b) is a rational number.
Therefore, x (an irrational number) = a rational number <em>This is a false statement which is a contradiction. So, the assumption was incorrect.</em>
Thus, the sum of a rational and irrational number is an irrational number. QED
