precal question

Question

Show that the point is on the unit circle.

		55/8
3/8

 

We need to show that the point satisfies the equation of the unit circle, that is, x² + y² =  .

x2 + y2	=			55/8
^2
+		^2
=
55/64
+
=

Answer 1

You left a square root sign off that needs to be on the 55

any point on the unit circle will have both x and y coordinates that are less than or equal to 1

55/8 is not a y coordinate that could be on the unit circle, but sqr55/8 is

x^2 + y^2 = 1

substitute x=3/8 and y = sqr55/8

(3/8)^2 + (sqr55/8)^2 = 1

9/64 + 55/64 = 1

64/64 = 1

(3/8, sqr55/8) is on the unit circle