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# Derivates = mind blown watch

1. Jack looks at his radio controlled airplane from an angle of under 30 degrees. The airplane flies horisontal at a speed at 15 m/s at a height of 100 metres. How fast is the angle changing?

This is probably totally wrong but. 90-30=60 so
tan(60)=x*15/100
x=11.54
tan(y)=x*15/100
sec^2(y)*y'=0.15
y'=0.15/sec^2(y)
y'(11.54)=0.15/sec^2(60)
y'(11.54)=0.6

The angle is changing with 0.6 every second

This doesnt feel right at all.
2. Draw a diagram for a fixed point then consider what happens slightly after. How much has the angle changed?
3. You need to work in radians if you're using calculus
4. (Original post by matt2k8)
You need to work in radians if you're using calculus

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Updated: January 21, 2010
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