Webwork Question

Professor Taylor,
For this hill-climbing problem I have tried computing the gradient and
making it into a positive unit vector, but I keep getting the wrong answer.
How do I do this problem?

Thanks,
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Since you don't specify, I guess you mean a problem like this one.18:

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The direction of maximal increase is in the direction of the gradient.  Since grad(z)=-0.18i-0.08j, the unit vector in this direction is u=grad(z)/|grad(z)|=(-0.18i-0.08j)/√(0.18^2+0.08^2)=-0.914i-0.406j.  The angle above the horizon can be obtained from the dot product of u with a ±i.