How do you find the exact value of #cos v = sqrt(2) / 4# in quadrant IV?

1 Answer
Johnson Z.
Dec 12, 2015

#290.7^@#

Explanation:

Assuming that you are trying to find the angle, #v#, you would have to use your calculator to find #v# since no special triangle has side lengths #sqrt(2)# or #4#.

Using your calculator:

#cosv=sqrt(2)/4#
#v=cos^-1((sqrt2)/4)#
#v~~69.3^@#

However, this angle is in the first quadrant. To find the angle, #v#, subtract #69.3^@# from #360^@# to find the angle in the fourth quadrant:

#360^@-69.3^@#
#=290.7^@#

#:.#, angle #v# is #290.7^@#.

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