The value of cos A is √(1 + x²)/ (1 - x²) /√1 + x
<h3>Trigonometric ratios</h3>
It is important to note that
sin A = opposite/ hypotenuse
cos A = adjacent/ hypotenuse
Then,
opposite = 
Hypotenuse = 
Let's find the adjacent side using the Pythagorean theroem



cos A = x/hypotenuse

cos A = √(1 + x²)/ (1 - x²) /√1 + x
Thus, the value of cos A is √(1 + x²)/ (1 - x²) /√1 + x
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Answer:
144 is correct
Step-by-step explanation:
13 - 1 is 12
12 times 12 = 144
144 divided by 2 is 72
72 times 2 is 144
Discriminant, D = b² - 4ac
x² - 4x + 5 = 0 comparing to ax² + bx + c = 0
a = 1, b = -4, c = 5
D = b² - 4ac = (-4)² - 4*1*5 = 16 - 20 = -4
In taking the square root of the discriminant of -4, √-4 = 2i = Not Real. So:
Discriminant is -4, so the equation has no real roots.
The second option is correct.