Find the exact value of the expression.

sin(arccos sqrt(5)/5)

remember Sin^2Theta+cos^2Theta=1

so if cosTheta= sqrt5/5, you can find sinTheta.

To find the exact value of the expression sin(arccos(sqrt(5)/5)), we can use the trigonometric identity relating the sine and the cosine of an angle. The identity is as follows:

sin(arccos(x)) = sqrt(1 - x^2)

First, let's find the value of x to substitute into the identity. In this case, x is sqrt(5)/5.

Now substituting into the identity, we get:

sin(arccos(sqrt(5)/5)) = sqrt(1 - (sqrt(5)/5)^2)

To simplify further, we square sqrt(5)/5:

= sqrt(1 - 5/25)
= sqrt(1 - 1/5)
= sqrt(4/5)
= 2/sqrt(5)

To rationalize the denominator, we multiply both the numerator and denominator by sqrt(5):

= (2 * sqrt(5))/(sqrt(5) * sqrt(5))
= 2sqrt(5)/5

Therefore, the exact value of the expression sin(arccos(sqrt(5)/5)) is 2sqrt(5)/5.