The 2nd one. The one that says CD=DA, DA=ZX, AC=YZ
Answer: B.pi/2
ABCD is a square
=> Δ ABD is a isosceles right triangle at A
using pythago theorem, we have:
AB² + AD² = BD²
=> 2AD² = 4
⇔ AD² = 2
⇒ AD = √2
through O, draw EF parallel to AD and BC
=> EF is diameter
because EF//AD => EF = AD = √2 (because circle O is inscribed the square ABCD)
=> the area of the circle is 
Step-by-step explanation:
I think the correct answer is c
ANSWER

EXPLANATION
Part a)
Eliminating the parameter:
The parametric equation is


From the first equation we make t the subject to get;


We put it into the second equation.


We differentiate to get;

At x=5,


The slope of the tangent is 2.
The equation of the tangent through
(5,6) is given by




Without eliminating the parameter,



At x=5,



This implies that,

The slope of the tangent is 2.
The equation of the tangent through
(5,6) is given by


