Question

Will fan and medal!
sec(-pi/3) - cot(-5pi/4)
I got -3 instead of 3
Cant use calculators

Answer 1

Yes 3 is correct.

Answer 2

http://www.wolframalpha.com/input/?i=sec%28-pi%2F3%29-cot%28-5pi%2F4%29

Answer 3

I dont know where I missed up when I did my math cause I got -3

Answer 4

@NathanJHW

Answer 5

You most likely just missed a negative sign.

Answer 6

Try it again from scratch.

Answer 7

At the last bit, is it supposed to be -2-1, when you're doing the work

Answer 8

@NathanJHW

Answer 9

Yes.

Answer 10

No sorry. It's 2 -(-1)

Answer 11

sec(-pi/3) = 2
cot(-5pi/4) = -1

Answer 12

Do the negatives in the original equation matter?

Answer 13

Yes because 2 - (-1) = 3 and 2 -1 = 1

Answer 14

@minisweet4

Look at sec(-pi/3)

I'd advise you to solve for the inverse, cos first. Notice this is NEGATIVE 60 degrees...That is the 4th quadrant...however in the 4th quadrant, Cos is POSITIVE.

You do your 30-60-90 triangle (i'm assuming you know this already)

and you get 1/2 as cos, so sec is 2.


NEXT

cot(-5pi/4)

That is negative 225 degrees, which ends up in the 2nd quadrant, NEGATIVE for cot and tan.

do your 45-45-90 triangle (again i'm assuming you know this, feel free to ask if you don't)

and you get 1, obviously -1 since this quadrant is negative.

2-(-)1=3

Answer 15

So basically when you have negative degrees, that doesn't necessarily make it negative, it all depends on the quadrant you end up in.