Mag and Direction of 3d Vectors

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SUMMARY

The discussion focuses on calculating the magnitude and direction of the vector C = -2i - 9j + 4k. The magnitude was correctly determined to be 10 using the formula √((-2)² + (-9)² + (4)²). To find the angle from the +z-axis, the formula cos(θ) = Az / |A| can be applied, where Az is the z-component (4) and |A| is the magnitude (10). For the direction in the xy-plane counterclockwise from the +x-axis, the angle can be calculated using the arctangent function: θ = arctan(y/x) = arctan(-9/-2).

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Loppyfoot
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Homework Statement


Find the magnitude and direction of the following vectors.
C = -2 i - 9 j + 4 k



I found that the magnitude was 10. By using the square root of (4+9+4).

I don't know how to find:
Angle from +z-axis
and the direction in xy plane counter clockwise from the +x axis.

Thanks
 
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gamma=Az divided by A
 
English please? is Az, 4k? Also, how do I find the direction in xy plane counter clockwise from the +x axis?
 

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