Venn Circle Integral
1. **Question 8:** Given the Venn diagram with sets A and B inside universal set U, values are:
- A only: 6 and 4 (total 10)
- B only: 3 and 5 (total 8)
- Intersection A ∩ B: 1 and 2 (total 3)
- Outside A and B but inside U: 7 and 8 (total 15)
(i) Find $m(A)$: Sum all elements in set A including intersection.
$$m(A) = 6 + 4 + 1 + 2 = 13$$
(ii) Calculate $P = \frac{m(A)}{m(U)}$:
$m(U)$ is sum of all numbers inside U:
$$m(U) = 6 + 4 + 1 + 2 + 3 + 5 + 7 + 8 = 36$$
Hence,
$$P = \frac{13}{36}$$
(iii) Find $m(A \cup B)$:
Union includes all elements in A, B and their intersection:
$$m(A \cup B) = 6 + 4 + 1 + 2 + 3 + 5 = 21$$
(iv) Find $(A \cap B) \cup (B \cap A)$:
Since intersection is commutative, this is just $A \cap B$:
$$m(A \cap B) = 1 + 2 = 3$$
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2. **Question 9:**
(a) Construct a tangent line at the point $T$ on the circle.
- The radius from the center meets the tangent line at $T$ at a right angle ($90^\circ$).
- The angle between another line segment inside the circle and the radius is $a$, so the angle between tangent and this segment at $T$ is $90^\circ - a$ by the complementary angle property.
(b) Given circle with center $O$, and angles:
(i) To find angle $a$:
Use the triangle angle sum property inside the circle.
Given angles include $110^\circ$ and angle $a$, so
$$a + 110^\circ + other\ angle = 180^\circ$$
Assuming other angle is $h$, then:
(ii) To find $h$ using the triangle angle sum,
$$h = 180^\circ - 110^\circ - a = 70^\circ - a$$
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3. **Question 10:**
(a) Evaluate the integral
$$\int (4x - \tan x) \, dx$$
Step 1: Use linearity to split the integral:
$$\int 4x \, dx - \int \tan x \, dx$$
Step 2: Integrate each separately:
$$\int 4x \, dx = 2x^2 + C_1$$
$$\int \tan x \, dx = - \ln|\cos x| + C_2$$
Therefore,
$$\int (4x - \tan x) \, dx = 2x^2 + \ln|\cos x| + C$$
where $C = C_1 + C_2$ is a constant.
(b)
(i) Sketch the curves $y=4x$ (a straight line through origin with slope 4) and $y=\tan x$ (periodic function with vertical asymptotes at $x=\pm \frac{\pi}{2}, \pm \frac{3\pi}{2}, \ldots$).
(ii) Shade the area between these curves represented by the integral. The area is between the two curves where $4x > \tan x$ over the domain considered.