SOLUTION: Let t be a real number with cos(t)=3/7, 3pi/2 < t < 2pi Find the exact value for each of the following: a. sin(t+3pi/2) b. sec(-t) c. cos(2pi) d.cos(4pi/3 - t) Pl

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Question 960796: Let t be a real number with cos(t)=3/7, 3pi/2 < t < 2pi Find the exact value for each of the following:
a. sin(t+3pi/2)
b. sec(-t)
c. cos(2pi)
d.cos(4pi/3 - t)

Please explain what these means how these are solved I have to understand!
Thank you! in advance
Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
Let t be a real number with , Find the exact value for each of the following: 
therefore angle t is in the 4th quadrant.

a. sin(t+3pi/2) 
Use the identity

b. sec(-t)
Multiplying an angle by -1 moves the angle t from 4th quadrant to 1st quadrant,
and the secant is the reciprocal of the cosine and is positive in 1st and 4th
quadrants. So

c. cos(2pi)
That's just 1.  It has nothing to do with t.

d.cos(4pi/3 - t) 
Use the identity 





Use identity 
since t is in quadrant 4 where sine is negative we use 
the negative:












  


Edwin
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