SOLUTION: If sin x<0 and tan x=-4/5, find the exact value of sec x

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Question 852378: If sin x<0 and tan x=-4/5, find the exact value of sec x
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
If sin x<0 and tan x=-4/5, find the exact value of sec x
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reference angle in Q4 in which sin<0, cos>0, tan<0
Identity:
...
calculator check:
tanx=-4/5 (in Q4)
x≈321.34˚
secx=1/cosx=1/cos(321.34)≈1.2806…
Exact value=√41/5≈1.2806…