SOLUTION: Express the value as a trigonometric function of an angle in quadrant 1. cos1290

Question 1031103: Express the value as a trigonometric function of an angle in quadrant 1.
cos1290
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Express the value as a trigonometric function of an angle in quadrant 1.
cos1290
-----
I'm going to assume that is 1290 degrees.
-----
1290/360 = 3.5833 = 3*360 + 0.5833*360
Note: We can drop the 3*360 ; that leaves us with 0.5833*360
---
0.5833*360 = 210 degrees
------
The reference angle for 210 degrees is 210-180 = 30 degrees
----
Note: 210 is in QIII where cos is negative.
---
Ans: cos(1290) = cos(210) = -cos(30)
------------------
Cheers,
Stan H.
---------------

RELATED QUESTIONS
Express the value as a trigonometric function of an angle in Quadrant 1.... (answered by stanbon)

Express tan(-315�) as a trigonometric function of an angle in Quadrant... (answered by Alan3354)

express cos120 as a function of an angle in quadrant... (answered by jim_thompson5910)

Express tan 245 degrees as a function of an angle in Quadrant... (answered by lwsshak3)

if angle is in Quadrant II, express the remaining trigonometric functions in terms of... (answered by Theo,Alan3354)

Express tan 315 degrees as a function of an angle in quadrant 1. Thank you so much for (answered by MathLover1)

Find the trigonometric function value of angle(delta). cos(delta)=8/9, with (delta) in (answered by stanbon)

find the value of the other 5 trigonometric function from the given function cos 3/5 in... (answered by Fombitz,Alan3354)

One of the primary trigonometric ratios for an angle is given, as well as the quadrant... (answered by math_helper,solver91311,MathTherapy)