1. **State the problem:**
Estimate the integral $$\int_5^7 2^{5 - \sqrt{x}} \, dx$$ using the trapezium rule with the given values of $y$ at $x = 5, 5.5, 6, 6.5, 7$.
2. **Recall the trapezium rule formula:**
For equally spaced points $x_0, x_1, \ldots, x_n$ with spacing $h$, the trapezium rule approximation is:
$$\int_{x_0}^{x_n} f(x) \, dx \approx \frac{h}{2} \left(y_0 + 2y_1 + 2y_2 + \cdots + 2y_{n-1} + y_n\right)$$
3. **Identify values:**
- $x$ values: 5, 5.5, 6, 6.5, 7
- $y$ values: 6.792, 6.298, 5.858, 5.466, 5.113
- Number of intervals $n=4$
- Step size $h = 5.5 - 5 = 0.5$
4. **Apply trapezium rule:**
$$\int_5^7 2^{5 - \sqrt{x}} \, dx \approx \frac{0.5}{2} \left(6.792 + 2(6.298 + 5.858 + 5.466) + 5.113\right)$$
Calculate the sum inside parentheses:
$$6.792 + 2(6.298 + 5.858 + 5.466) + 5.113 = 6.792 + 2(17.622) + 5.113 = 6.792 + 35.244 + 5.113 = 47.149$$
So,
$$\int_5^7 2^{5 - \sqrt{x}} \, dx \approx \frac{0.5}{2} \times 47.149 = 0.25 \times 47.149 = 11.78725$$
Rounded to 2 decimal places:
$$\boxed{11.79}$$
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5. **Part (b)(i): Estimate $$\int_5^7 2^{6 - \sqrt{x}} \, dx$$**
Note that:
$$2^{6 - \sqrt{x}} = 2^{1} \times 2^{5 - \sqrt{x}} = 2 \times 2^{5 - \sqrt{x}}$$
Therefore,
$$\int_5^7 2^{6 - \sqrt{x}} \, dx = \int_5^7 2 \times 2^{5 - \sqrt{x}} \, dx = 2 \times \int_5^7 2^{5 - \sqrt{x}} \, dx$$
Using the answer from part (a):
$$= 2 \times 11.78725 = 23.5745$$
Rounded to 2 decimal places:
$$\boxed{23.57}$$
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6. **Part (b)(ii): Estimate $$\int_5^7 (3 + 2^{5 - \sqrt{x}}) \, dx$$**
Split the integral:
$$\int_5^7 3 \, dx + \int_5^7 2^{5 - \sqrt{x}} \, dx$$
Calculate the first integral:
$$3 \times (7 - 5) = 3 \times 2 = 6$$
Add the result from part (a):
$$6 + 11.78725 = 17.78725$$
Rounded to 2 decimal places:
$$\boxed{17.79}$$
Trapezium Integration C50823
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