The answer is the third one -2.
Let the two sides of a right triangle be equal to one, which means that the hypotenuse is √2
Since cosa=adjacent side / hypotenuse
cos45=1/√2
We can rationalize the denominator by multiplying numerator and denominator by √2
√(2)/2
or if you prefer: √(1/2)
Can you show the problem? Those are the questions but I need the actual graph.