+0

# this interval indicate to which quarter

0
512
8
+1832

this interval indicate to which quarter

Aug 1, 2014

#1
+121078
+10

This is just a Pythagorean right triangle in the 4th quad where x = 5, y = -12, and the hypoteneuse (r) = 13.

And the cosine is given by....

x/r  = 5/13  = Answer (c)

Aug 1, 2014

#1
+121078
+10

This is just a Pythagorean right triangle in the 4th quad where x = 5, y = -12, and the hypoteneuse (r) = 13.

And the cosine is given by....

x/r  = 5/13  = Answer (c)

CPhill Aug 1, 2014
#2
+1832
0

sorry .. but how do you know that it is in the 4th quad !

and why you put y=-12 !!

Aug 1, 2014
#3
+121078
+5

It's in the 4th quadrant because the angle "x" lies between -pi/2  and 0.....

And remember that in the 4th quadrant, x is positive and y is negative. And the tanx = y/x = -12/5

Does that make sense, xvxvxv ???

Aug 1, 2014
#4
+1832
0

I think that I forgot this information

if I not mistaken I think that there is a circle that illustrate this information !

do you know it .. ! because it will help me understand

Aug 1, 2014
#5
+121078
+5

http://www.themathpage.com/aTrig/unit-circle.htm

Aug 1, 2014
#6
+1832
0

thanx my friend

Aug 1, 2014
#7
+115747
+5

Remember

All Stations To Central

All are positive in the first quad

sin is pos in the second

tan is pos in the third and

cos is pos in the 4th.

Aug 1, 2014
#8
+121078
+5

We used to say "All Students Take Calculus"...but I like "All Stations To Central," too!!  (It sounds like something right out of the old TV program..."Car 54, Where Are You??" )

Aug 1, 2014