Question

I'll give a medal!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Can someone explain to me the relationship between sine and cosine. I will give a medal!

Answer 1

So do you know the definition of sine?

Answer 2

yes

Answer 3

go ahead

Answer 4

ok... so here is a right triangle



so looking at the diagram,

what is sin(x)

and what is cos(90 - x)

Answer 5

It is oppisate of hypo.

Answer 6

It is also known as the context of a right triangle

Answer 7

Ok, so the def. is where we should start, sine is the side opposite our angle(in this case A) divided by the Hypotenuse

Answer 8

They're the exact same thing, just shifted by a constant.
\[\sin(x)=\cos(x-\frac{\pi}{2})\]

Answer 9

There is an amusing story told by math teachers(now a days it may be considered insensitive, but it is still useful) Please, read: http://teacherweb.com/WA/LakesHighSchool/MrKuras/Queen-Sohcahtoa.pdf

Answer 10

I know SohCahToa

Answer 11

ok, so which relationship don't you understand?

Answer 12

well cosine means "the complement of the sine." and I dont really get that

Answer 13

well its simply

sin(x) = b/c from the diagram

and then

cos(90 - x) = b/c so the same value

and taking a look at

cos(x) = a/c

which sin(90 -x) = a/c

so the same thing...

Answer 14

ok so,
How many degrees are in a triangle?

Answer 15

I still don't really get it. I'll ask my teacher about it tomorrow. Thanks for the help

Answer 16

180 degrees

Answer 17

now, the word complement implies an angle that when added to another angle adds up to 90 degrees

Answer 18

ok fibon can u give campbell a medal please

Answer 19

so we know that there are 180 degrees in the ∆, but we also have a right angle

Answer 20

yes a right triangle one angle is 90 degrees

Answer 21

so, we now know that angle A and B are complementary

Answer 22

or they add up to 90

Answer 23

yes

Answer 24

i get it now thanks

Answer 25

np have a good one