Evaluate a definite integral or solve for unknowns by exploiting functional equations, symmetry (e.g., f(x) + f(a−x) relations), or clever substitutions that simplify the integrand.
Let $f(x) = \frac{2^{x+2} + 16}{2^{2x+1} + 2^{x+4} + 32}$. Then the value of $8\left(f\left(\frac{1}{15}\right) + f\left(\frac{2}{15}\right) + \ldots + f\left(\frac{59}{15}\right)\right)$ is equal to (1) 92 (2) 118 (3) 102 (4) 108
The value of $\int_{-\pi/6}^{\pi/6} \left(\frac{\pi + 4x^{11}}{1 - \sin(|x| + \frac{\pi}{6})}\right)dx$ is equal to (A) $8\pi$ (B) $7\pi$ (C) $5\pi$ (D) $4\pi$
Computer Science and Computer Science \& Philosophy applicants should turn to page 14. In this question we fix a real number $\alpha$ which will be the same throughout. We say that a function $f$ is bilateral if $$f ( x ) = f ( 2 \alpha - x )$$ for all $x$. (i) Show that if $f ( x ) = ( x - \alpha ) ^ { 2 }$ for all $x$ then the function $f$ is bilateral. (ii) On the other hand show that if $f ( x ) = x - \alpha$ for all $x$ then the function $f$ is not bilateral. (iii) Show that if $n$ is a non-negative integer and $a$ and $b$ are any real numbers then $$\int _ { a } ^ { b } x ^ { n } \mathrm {~d} x = - \int _ { b } ^ { a } x ^ { n } \mathrm {~d} x$$ (iv) Hence show that if $f$ is a polynomial (and $a$ and $b$ are any reals) then $$\int _ { a } ^ { b } f ( x ) \mathrm { d } x = - \int _ { b } ^ { a } f ( x ) \mathrm { d } x$$ (v) Suppose that $f$ is any bilateral function. By considering the area under the graph of $y = f ( x )$ explain why for any $t \geqslant \alpha$ we have $$\int _ { \alpha } ^ { t } f ( x ) \mathrm { d } x = \int _ { 2 \alpha - t } ^ { \alpha } f ( x ) \mathrm { d } x$$ If $f$ is a function then we write $G$ for the function defined by $$G ( t ) = \int _ { \alpha } ^ { t } f ( x ) \mathrm { d } x$$ for all $t$. (vi) Suppose now that $f$ is any bilateral polynomial. Show that $$G ( t ) = - G ( 2 \alpha - t )$$ for all $t$. (vii) Suppose $f$ is a bilateral polynomial such that $G$ is also bilateral. Show that $G ( x ) = 0$ for all $x$. If you require additional space please use the pages at the end of the booklet
The polynomial function $f ( x )$ is such that $f ( x ) > 0$ for all values of $x$. Given $\int _ { 2 } ^ { 4 } f ( x ) d x = A$, which one of the following statements must be correct? A $\int _ { 0 } ^ { 2 } [ f ( x + 2 ) + 1 ] d x = A + 1$ B $\quad \int _ { 0 } ^ { 2 } [ f ( x + 2 ) + 1 ] d x = A + 2$ C $\int _ { 2 } ^ { 4 } [ f ( x + 2 ) + 1 ] d x = A + 1$ D $\int _ { 2 } ^ { 4 } [ f ( x + 2 ) + 1 ] d x = A + 2$ E $\quad \int _ { 4 } ^ { 6 } [ f ( x + 2 ) + 1 ] d x = A + 1$ F $\quad \int _ { 4 } ^ { 6 } [ f ( x + 2 ) + 1 ] d x = A + 2$
$f ( x )$ is a function defined for all real values of $x$. Which one of the following is a sufficient condition for $\int _ { 1 } ^ { 3 } f ( x ) d x = 0$ ? A $f ( 2 ) = 0$ B $f ( 1 ) = f ( 3 ) = 0$ C $f ( - x ) = - f ( x )$ for all $x$ D $f ( x + 2 ) = - f ( 2 - x )$ for all $x$ E $\quad f ( x - 2 ) = - f ( 2 - x )$ for all $x$
The function $\mathrm { f } ( x )$ is defined for all real values of $x$. Which of the following conditions on $\mathrm { f } ( x )$ is/are necessary to ensure that $$\int _ { - 5 } ^ { 0 } \mathrm { f } ( x ) \mathrm { d } x = \int _ { 0 } ^ { 5 } \mathrm { f } ( x ) \mathrm { d } x$$ Condition I: $\quad \mathrm { f } ( x ) = \mathrm { f } ( - x ) $ for $- 5 \leq x \leq 5$ Condition II: $\mathrm { f } ( x ) = c$ for $- 5 \leq x \leq 5$, where $c$ is a constant Condition III: $\mathrm { f } ( x ) = - \mathrm { f } ( - x ) $ for $- 5 \leq x \leq 5$ A none of them B I only C II only D III only E I and II only F I and III only G II and III only H I, II and III
For the function $f$ whose graph is given above in the rectangular coordinate plane $$\begin{aligned}
& \int_{a}^{c} |f(x)|\, dx = 20 \\
& \int_{a}^{c} f(x)\, dx = 8
\end{aligned}$$ the equalities are satisfied. What is the value of $$\int_{a/2}^{b/2} f(2x)\, dx$$ ? A) $-3$ B) $-4$ C) $-5$ D) $-6$ E) $-7$
For a continuous function $f$ defined on the set of real numbers and the function $g(x) = 2x + 2$ defined as, $$\begin{aligned}
& \int_{-1}^{1} f(g(x))\, dx = 18 \\
& \int_{2}^{4} g(f(x))\, dx = 18
\end{aligned}$$ are satisfied. Accordingly, what is the value of the integral $\int_{0}^{2} f(x)\, dx$? A) 20 B) 23 C) 26 D) 29 E) 32