Photo AI

Figure 2 shows a sketch of the graph with equation y = 2|x + 4| - 5 The vertex of the graph is at the point P, shown in Figure 2 - Edexcel - A-Level Maths Pure - Question 11 - 2020 - Paper 2

Question icon

Question 11

Figure-2-shows-a-sketch-of-the-graph-with-equation--y-=-2|x-+-4|---5--The-vertex-of-the-graph-is-at-the-point-P,-shown-in-Figure-2-Edexcel-A-Level Maths Pure-Question 11-2020-Paper 2.png

Figure 2 shows a sketch of the graph with equation y = 2|x + 4| - 5 The vertex of the graph is at the point P, shown in Figure 2. (a) Find the coordinates of P. ... show full transcript

Worked Solution & Example Answer:Figure 2 shows a sketch of the graph with equation y = 2|x + 4| - 5 The vertex of the graph is at the point P, shown in Figure 2 - Edexcel - A-Level Maths Pure - Question 11 - 2020 - Paper 2

Step 1

Find the coordinates of P.

96%

114 rated

Answer

To find the vertex of the equation, we analyze the expression inside the absolute value:

x+4=0x=4x + 4 = 0 \Rightarrow x = -4

Substituting this back into the equation:

y = 2|-4 + 4| - 5 = 2|0| - 5 = -5.

Thus, the coordinates of point P are P(-4, -5).

Step 2

Solve the equation 3x + 40 = 2|x + 4| - 5.

99%

104 rated

Answer

First, isolate the absolute value term:

3x+40+5=2x+43x+45=2x+43x + 40 + 5 = 2|x + 4| \Rightarrow 3x + 45 = 2|x + 4|

Now we divide into two cases based on the definition of absolute values.

Case 1: For x+40x+4=x+4x + 4 \geq 0 \Rightarrow |x + 4| = x + 4

Substituting this into the equation:

3x+45=2(x+4)3x+45=2x+8x=373x + 45 = 2(x + 4) \Rightarrow 3x + 45 = 2x + 8 \Rightarrow x = -37

Case 2: For x+4<0x+4=(x+4)x + 4 < 0 \Rightarrow |x + 4| = - (x + 4)

Substituting this into the equation:

3x+45=2(x4)3x+45=2x85x=53x=10.63x + 45 = 2(-x - 4) \Rightarrow 3x + 45 = -2x - 8 \Rightarrow 5x = -53 \Rightarrow x = -10.6

Thus, the solutions to the equation are x=10.6x = -10.6 and x=37x = -37.

Step 3

Find the range of possible values of a, writing your answer in set notation.

96%

101 rated

Answer

To find the range of a, we consider the intersection of the lines:

Setting the equations equal to one another:

ax=2x+45ax = 2|x + 4| - 5

This will depend on the value of aa. The line will intersect the absolute function once if the slope aa does not exceed the steepness of the graph defined by:

We find the values of a for one intersection:

  1. From the vertex of the graph (x=4x = -4), the maximum slope of the absolute function is 2.
  2. Solving gives us the intervals needed:
    • For intersection: a<2a < 2
    • Also consider the line can cross between negative yy and positive segments.

Thus the final answer in set notation: {a:a2.125}{a:a>2}\{ a : a \leq 2.125 \} \cup \{ a : a > 2 \}

Join the A-Level students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;