Question

Can someone help me with this problem?
Evaluate the expression, using exact values (use unit circle)
sec^2(60deg) + 3cos(210deg)

Answer 1

\(\cos(60º) = 1/2\)

\(\cos(30º) = \sqrt{3}/2\)

These are standard values you should memorize. This is just about all you need to solve the problem.

Answer 2

I know the values for them I just have a problem putting it in the equation also when you solve it do you ignore the exponent?

Answer 3

What's preventing you from doing it?

\(\sec(x) = 1/\cos(x)\)

Use that and see where it leads.

Answer 4

The exponent the answer I got for the problem was -3sqrt3

Answer 5

The exponent is what is confusing me

Answer 6

Okay, how did you get that?

\(\cos(60º) = 1/2\)

\(\sec(60º) = 2\)

\(\sec^{2}(60º) = (2)^{2} = 4\)

Perhaps your book or teacher failed to tell you that \(\sec^{2}(x) = [\sec(x)]^{2}\)?

Answer 7

I guess so because I knew I had to use the exponent our teacher just really didn't explain it well to us

Answer 8

The notation is a little weird, but it is EVERYWHERE, so we all just have to get used to it. That sort of notation is kind of rare, but you will see it over and over with trigonometric functions.

Answer 9

How I go the answer was like this..
2 + 3(-sqrt3/2)
2 - 3sqrt3/2
Then I crossed out the 2's and got -3sqrt3

Answer 10

I already showed you how the secant piece is 4.

\(3\cos(210º) = -3\cos(30º) = -3(\sqrt{3}/2)\)

Thus, \(4 - 3\sqrt{3}/2 = \dfrac{8 - 3\sqrt{3}}{2}\)

Answer 11

There is no cancelling of 2s. There is no such thing as cancelling.

Answer 12

Oh, ok I redid the problem a couple of times and came up with the 8 - 3sqrt3 / 2 answer but I just have one question would you divide the 8 with the 2 to make it 4 - 3sqrt3 as the answer?

Answer 13

I meant reduce it

Answer 14

You must review your Order of Operations.

8 - 3sqrt(3)/2 is NOT correct.

[8 - 3sqrt(3)]/2 IS correct.

Do you see the difference?

Answer 15

4 - 3sqrt(3)/2 = [8 - 3sqrt(3)]/2

Answer 16

I see the difference you use the brackets to have all the numbers inside be divided by 2

Answer 17

Right. Without the brackets, only the numbers/variables next to the 2 are divided by the 2.

4 - 3sqrt(3)/2 = \(4 - \dfrac{3\sqrt{3}}{2}\)

[8 - 3sqrt(3)]/2 = \(\dfrac{8 - 3\sqrt{3}}{2}\)

Answer 18

Ok well thank you for the help :)