<PRE><B>Question 253677</B>
1.) if sin x= (12/13), cos y=(3/5) and x and y are acute angles, the value of cos(x-y) is 
a.(21/65) b.(63/65) c. -(14/65) d. -(33/65)
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cos(x-y) = cos(x)cos(y)+sin(x)sin(y)
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Since sin(x) = 12/13, cos(x)=5/13
Since cos(y) = 3/5, sin(y) = 4/5
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Therefore:
cos(x-y) = (5/13)(3/5)+(12/13)(4/5) = (63/65)
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2.) if the tangent of an angle is negative and its secant is positive, in which quadrant does the angle terminate
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tangent is negative in the 2nd and 4th quadrants
secant is positive in the 1st and 4th quadrants.
Therefore the angle is in the 4th quadrant.
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Cheers,
Stan H.</PRE>