A circle C has centre M (6, 4) and radius 3 - Edexcel - A-Level Maths Pure - Question 8 - 2008 - Paper 2
Question 8
A circle C has centre M (6, 4) and radius 3.
(a) Write down the equation of the circle in the form
$(x - a)^2 + (y - b)^2 = r^2$.
(b) Show that the angle TMQ is 1... show full transcript
Worked Solution & Example Answer:A circle C has centre M (6, 4) and radius 3 - Edexcel - A-Level Maths Pure - Question 8 - 2008 - Paper 2
Step 1
Write down the equation of the circle in the form $(x - a)^2 + (y - b)^2 = r^2$
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Answer
To write the equation of the circle with center M (6, 4) and radius 3, we use the standard form of the equation of a circle.
Substituting the values, we have:
(x−6)2+(y−4)2=32
Thus, the equation of the circle is:
(x−6)2+(y−4)2=9
Step 2
Show that the angle TMQ is 1.0766 radians to 4 decimal places
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Answer
To find the angle TMQ, we need to determine the coordinates of the points T and Q along with point P (12, 6).
Calculate the slope of line MP:
The coordinates of M are (6, 4) and P are (12, 6).
The slope, mMP=x2−x1y2−y1=12−66−4=62=31.
The tangent at point T, which lies on the circle, is perpendicular to MP, so:
mTQ=−mMP1=−3.
Using the coordinates of T and Q (which can be calculated), the angle heta can be found using:
θ=tan−11+mTMP⋅mTQmTMP−mTQ
By substituting the respective slopes, we can derive the tangent and then calculate the angle TMQ, confirming it equals approximately 1.0766 radians.
Step 3
Find the area of the shaded region TPQ
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Answer
The shaded region TPQ can be computed by finding the area of triangle TPQ and subtracting the area of the sector formed by the circle.
Area of Triangle TPQ:
Use the formula:
Area=21×base×height
The base TP can be calculated from the coordinates of points T and P.
And the height is the perpendicular distance from Q to line TP.
Area of the Sector:
The angle at the center M corresponding to the arc TQ can be calculated based on the angle TMQ.
Then, using the radius, the area of the sector is:
Areasector=21r2θ where heta is in radians.
Final Area Calculation:
The area of the shaded region is:
Areashaded=Areatriangle−Areasector
Substitute the values to arrive at the final answer accurate to three decimal places.