What is the relationship between cos(90degrees) and cos(-90°)?

The relationship between the two is that they are equal.

Step-by-step explanation:

Since y = cosx is a even function, that means that cosx = cos(-x). Therefore, cos 90 degrees = cos -90 degrees.

We can also test this out:

cos 90 = 0

cos -90 = cos 270 = 0

Therefore, this came to the same conclusion as our first solution.

I hope this helps! :)

center (1,3) with radius 6

step-by-step explanation:

we must complete the square to find the center and radius of the circle.

first make sure the x and y squared terms have 1 as their coefficients. we also make sure x and y terms together.

we now create space between the x and y terms with parenthesis.

we complete the square by taking the middle terms -2x and the -6y - divide each and square them.

we add the squares to both sides.

simplify.

and write the quadratics in factored form.

the center is (h,k) or (1,3). the radius is the square root of 36 which is 6.