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The curve C has equation y = (2x - 3)^ 5 The point P lies on C and has coordinates (w, -32) - Edexcel - A-Level Maths Pure - Question 22 - 2013 - Paper 1

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The curve C has equation y = (2x - 3)^ 5 The point P lies on C and has coordinates (w, -32). Find a) the value of w; b) the equation of the tangent to C at the ... show full transcript

Worked Solution & Example Answer:The curve C has equation y = (2x - 3)^ 5 The point P lies on C and has coordinates (w, -32) - Edexcel - A-Level Maths Pure - Question 22 - 2013 - Paper 1

Step 1

Find the value of w;

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Answer

To find the value of w, we start by substituting y = -32 into the equation of the curve:

32=(2w3)5-32 = (2w - 3)^5

Taking the fifth root of both sides, we can solve for (2w - 3):

2w3=(32)1/5=22w - 3 = (-32)^{1/5} = -2

Thus, we get:

2w=2+32w = -2 + 3 2w=12w = 1

Dividing both sides by 2 gives:

w = rac{1}{2} \\ or \\\ w = 0.5

Step 2

the equation of the tangent to C at the point P in the form y = mx + c, where m and c are constants.

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Answer

To find the equation of the tangent line at point P, we first need to differentiate the curve equation:

rac{dy}{dx} = 5(2x - 3)^4 imes 2 = 10(2x - 3)^4

Next, we evaluate the derivative at x = w = 0.5:

rac{dy}{dx} igg|_{x=0.5} = 10(2(0.5) - 3)^4 = 10(-2)^4 = 10(16) = 160

Now that we have the gradient (m), we can write the equation of the tangent line in point-slope form:

Using the point (0.5, -32), the equation is given by:

y - (-32) = 160(x - 0.5) \

This simplifies to:

y + 32 = 160x - 80 \

Rearranging gives the final tangent line equation:

y=160x112y = 160x - 112

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