Basic Electricity (what i should know but don't)

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To calculate the maximum resistance of a filament lamp from a V-I graph, accurately draw a tangent line at the steepest point, typically near the origin. Construct a right-angled triangle using this tangent as the hypotenuse. The maximum resistance can be found by dividing the change in voltage by the change in current along the tangent line. This method allows for an accurate measurement of resistance at that specific point on the curve. Careful attention to detail in drawing the tangent is essential for precise calculations.
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i have been given this question

Figure 1 shows a graph of V against I for a filament lamp. Calculate the maximum resistance of the lamp over the range shown by the graph,

now i have a somewhat vague attempt and its to measure the tangent of the line (i can't upload the graph sorry)

how do i take a tangent of a curved line accurately and then calculate the maximum resistance


thank you for your help
 
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You just need to take a little time and care drawing your tangent.The graph should be steepest at the origin where the resistance is highest..Draw your tangent as long as you can ,construct a right angled triangle where the tangent becomes the hypotenuse and divide the change of voltage by the change of current(tan theta)
 

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