SOLUTION: Use trig identities and the given information to determine the exact value Secx= -8/5, pi <or equal to X <or equal to 3pi/2, find cosx

Algebra.Com
Question 1022071: Use trig identities and the given information to determine the exact value
Secx= -8/5, pi

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!

--------
Use trig identities and the given information to determine the exact value
Secx= -8/5, pi <= X <= 3pi/2, find cosx
-----
By definition, sec = r/x
----
Since X is in QIII, x is negative::
Therefore: r = 8 and x = -5
-----
Then cos(x) = x/r = 1/sec(x) = 1/(-8/5) = -5/8
-----------------
Cheers,
Stan H.
---------------

RELATED QUESTIONS

Use your trig identities and the given information to determine the exact value... (answered by fractalier)
Use the given information to determine the exact trigonometric value sin theta=-1/5,... (answered by stanbon)
how do you find the exact value of tan theta when given that sin theta= 3/5 and pi/2 < or (answered by lwsshak3)
Given sec(theta)=10 and 3pi/2 < or equal to theta < or equal to 2pi, find the exact... (answered by lwsshak3)
Use the given information to determine the exact trigonometric value. Find csc(theta)... (answered by solver91311)
solve for x in the equation cscx=-1.5, where pi (answered by Alan3354)
If sin(theta)= (sqrt2)/5, and pi/2 < theta < pi, then find the exact value of tan(2theta) (answered by lwsshak3)
1)Find the value of t and determine the quadrant cos t= -4/5 2)If the terminal point... (answered by solver91311)
use the coordinates for familiar angles on the unit circle to solve the equation sec(x)=- (answered by ewatrrr)