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# I have sec 885 degrees as problem and it wants me to find the exact value. The answer is radical 2, but the calculator gave me -1.41. How do

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I have sec 885 degrees as problem and it wants me to find the exact value. The answer is radical 2, but the calculator gave me -1.41. How do I get radical two on my calculator.

Feb 2, 2015

#1
+27342
+10

I think you must mean 855 degrees (not 885 degrees).  Most calculators won't display results as fractions, but you can do this by continuing to subtract 360 degrees from this until you get to 135 degrees (855 - 360 -360 = 135).  sec, like cos,  is negative here (sec = 1/cos).

Imagine a line on a graph from the origin (0, 0) to the point (-1, 1).  This is at angle of 135 degrees to the positive x-axis (45 degrees to the negative x-axis).

The length of the diagonal of this line is √(1^2 -(-1)^2) = √2

Then sec(135) = √2/(-1) = -√2

.

Feb 2, 2015

#1
+27342
+10

I think you must mean 855 degrees (not 885 degrees).  Most calculators won't display results as fractions, but you can do this by continuing to subtract 360 degrees from this until you get to 135 degrees (855 - 360 -360 = 135).  sec, like cos,  is negative here (sec = 1/cos).

Imagine a line on a graph from the origin (0, 0) to the point (-1, 1).  This is at angle of 135 degrees to the positive x-axis (45 degrees to the negative x-axis).

The length of the diagonal of this line is √(1^2 -(-1)^2) = √2

Then sec(135) = √2/(-1) = -√2

.

Alan Feb 2, 2015