Ex 10.1, 10 - Find angle between x-axis and line joining - Slope - Finding slope

  1. Chapter 10 Class 11 Straight Lines
  2. Serial order wise

Transcript

Ex10.1, 10 Find the angle between the x-axis and the line joining the points (3, –1) and (4, –2). First we find slope of line joining the points (3, –1) and (4, –2). We know that slope of line passing through (x1, y1) and (x2, y2) is m = (𝑦_2 βˆ’ 𝑦_1)/(π‘₯_2 βˆ’ π‘₯_1 ) Here x1 = 3, y1 = –1 & x2 = 4, y2 = –2 Slope of line joining (3, –1) and (4, –2) is m = ( βˆ’ 2 βˆ’ ( βˆ’ 1))/(4 βˆ’ 3) = ( βˆ’ 2 + 1)/(4 βˆ’ 3) = ( βˆ’ 1)/1 = –1 Now, Slope = m = tan ΞΈ where ΞΈ is the angle between line and positive x-axis So m = tan ΞΈ –1 = tan ΞΈ tan ΞΈ = –1 tan ΞΈ = tan (135Β°) ΞΈ = 135Β° So, Required angle = ΞΈ = 135Β°

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