SOLUTION: wind speed varies in the first twenty meters above the ground. For a particular day, let f(x) = 9.8 ln x +4.9 compute the wind speed x meters above the ground. At what height is th

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: wind speed varies in the first twenty meters above the ground. For a particular day, let f(x) = 9.8 ln x +4.9 compute the wind speed x meters above the ground. At what height is th      Log On


   

Question 544505: wind speed varies in the first twenty meters above the ground. For a particular day, let f(x) = 9.8 ln x +4.9 compute the wind speed x meters above the ground. At what height is the wind speed 7 meters per second? Round results to the nearest hundredth.
I cannot figure out how to do this problem and could really use some help! thanks!
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
wind speed varies in the first twenty meters above the ground. For a particular day, let f(x) = 9.8 ln x +4.9 compute the wind speed x meters above the ground. At what height is the wind speed 7 meters per second? Round results to the nearest hundredth.
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f(x) = 9.8 ln x +4.9
7= 9.8 ln x +4.9
7-4.9= 9.8 ln x
7-4.9= 9.8 ln x
2.1/9.8=ln x
.2143=ln x
convert to exponential form of logs: base(e) raised to log of number(.2143)= number(x)
x=e^.2143≈1.24
ans:
At a wind speed of 7 meters per second, the wind is 1.24 meters above the ground