Question 1174405:  1.Given: cos theta = 5/13, theta is in quadrand I. Find:tan  theta. 
2.Given:sin theta=1/3,theta is in quadrand II. Find:cos theta. 
3.Given:tan theta =2/3 theta is in quadrand IV. Find:sin theta. 
4.Given:sec theta=9/8,theta is in quadrand III . Find:csc theta. 
5.Given:csc theta= 2, sec theta < 0. Find tan theta. 
6:Given:cot theta= 8/15, sin theta < 0.find cos theta.  
 Answer by Theo(13342)      (Show Source): 
You can  put this solution on YOUR website! 1.Given: cos theta = 5/13, theta is in quadrant I. Find:tan theta.
 
 
arccos(5/13) = 67.38013505 degrees. 
that's in quadrant 1. 
equivalent angle in quadrant 1 is the same. 
tan(67.38013505) = 2.4
 
 
2.Given:sin theta=1/3,theta is in quadrant II. Find:cos theta.
 
 
arcsin(1/3) = = 19.47122063 degrees. 
that's in quadrant 1. 
equivalent angle in quadrant 2 is 180 minus that = 160.5287794. 
cos(that) = -.9428090416. 
cosine function is negative in quadrant 2.
 
 
3.Given:tan theta = 2/3 theta is in quadrant IV. Find:sin theta.
 
 
arctan(2/3) = 33.69006753 degrees. 
that's in quadrant 1. 
equivalent angle in quadrant 4 is 360 minus that = 326.3099325. 
sin(that) = -.5547001962. 
sine function is negative in quadrant 4.
 
 
4.Given:sec theta=9/8,theta is in quadrant III . Find:csc theta.
 
 
sec(theta) = 1/cos(theta), therefore: 
since secant = 1/cosine, then: 
1/cos(theta) = 9/8. 
solve for cos(theta) to get cos(theta) = 1/(9/8) = 8/9. 
arccos(8/9) = 27.26604445 degrees. 
that's in quadrant 1. 
equivalent angle in quadrant 3 is 180 plus that = 207.2660445 
csc(that) = 1/sin(that) = -2.182820625. 
cosecant is negative in third quarter because cosecant = 1/sine and sine is negative in quadrant 3.
 
 
 
5.Given:csc theta= 2, sec theta < 0. Find tan theta.
 
 
csc(theta) = 1/sin(theta). 
solve for sin(theta) to get sin(theta) = 1/2. 
arcsin(1/2) = 30 degrees. 
that's in quadrant 1. 
sec(theta) is smaller than 0. 
sec(theta) is equal to 1/cos(theta) and is negative in quadrants 2 and 3. 
the equivalent angle in quadrant 2 is 180 - 30 = 150 degrees. 
tan(150) = -.5773502692. 
tangent function is negative in quadrant 2. 
the equivalent angle in quadrant 3 is 180 + 30 = 210 degrees. 
tan(210) = .5773502692. 
the tangent function is positive in quadrant 3. 
this is because sine is negative and cosine is negative in quadrant 3 and tangent = sin/cos = negative/negative = positive in quadrant 3. 
it's the same value as in quadrant 2 only it's negative in quadrant 2 and positive in quadrant 3.
 
 
6:Given:cot theta= 8/15, sin theta < 0.find cos theta.
 
 
cot(theta) = 1/tan(theta) = 8/15 
solve for tan(theta) to get tan(theta) = 15/8. 
arctan(15/8) = 61.92751306 degrees. 
that's in quadrant 1. 
sin(theta) is negative in quadrant 3 and 4. 
equivalent angle in quadrant 3 is 180 plus that = 241.9275131 degrees. 
cos(that) = -.4705882353. 
cosine is negative in quadrant 3. 
equivalent angle in quadrant 4 is 360 minus that = 298.0724869 degrees. 
cos(that) = .4705882353. 
cosine is positive in quadrant 4.
 
 
if you are confused or have any questions about any of this, let me know and i'll explain as best i can.
 
 
theo 
 
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