Use a half-angle identity to find the exact value of cos15 .
a.
(sqrt2+sqrt3)/2
c.
(sqrt2-sqrt3)/2
b.
sqrt2+sqrt3
d.
sqrt2-sqrt3

Option a.

Step-by-step explanation:

In this question we have to find out the exact value of cos 15 by half angle identity.

As we know that is the half angle identity.

From half this identity we can write cos15 as

=

cos 15 =

          =

          =

So Option a.  is the right option.

3/4 ÷ 3/4

step-by-step explanation:

basically divide any proper fraction with itself to fit the criteria.

so if we are using 3/4, then:

3/4 ÷ 3/4 = 1

so 1 is the quotient.

and the numerators for both these fractions is 3.   and if we divide the numerators:

3 ÷ 3 = 1

we see that quotient is equal to our original quotient as well.

answer: the anser is 3

step-by-step explanation:

c- 2o is equal to 9