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Let $S=\left\{t\in\mathbb{R}: f(x)=|x-\pi|\cdot(e^{|x|}-1)\sin|x|\right.$ is not differentiable at $t\}$. Find $S$.
Check $x=0$: $f(x)=|x-\pi|(e^{|x|}-1)\sin|x|$. Near $x=0$, both $(e^{|x|}-1)$ and $\sin|x|$ have factors of $|x|$, so $f(x)\approx |x-\pi|\cdot|x|^2$ near 0, which is differentiable at 0.
Check $x=\pi$: near $\pi$, $(e^{|x|}-1)\sin|x|$ is smooth and non-zero ($e^\pi\sin\pi=0$!). Since $\sin\pi=0$, the product $(e^{|x|}-1)\sin|x|$ vanishes at $\pi$, making $f(x)=0$ near $\pi$ — wait, $\sin\pi=0$, so $f(\pi)=0$. Checking differentiability more carefully shows $f$ is differentiable at $\pi$ too.
Therefore $S=\boldsymbol{\emptyset}$.
Which statements about capital income and revenue income are correct?
- Revenue income includes amounts received from renting out part of business premises.
- Capital income includes amounts received from the sale of non-current assets.
- Capital income includes loans taken by a business.
Option B (1 and 2 only) is correct.
- Statement 1 (True): Rental income is regular and recurring — revenue income.
- Statement 2 (True): Proceeds from selling a non-current asset are a one-off receipt — capital income.
- Statement 3 (False): Loans are liabilities, not capital income.
Evaluate $\sin^{-1}\!\left(\dfrac{12}{13}\right)-\sin^{-1}\!\left(\dfrac{3}{5}\right)$.
Let $A=\sin^{-1}(12/13)$: $\sin A=12/13,\ \cos A=5/13$.
Let $B=\sin^{-1}(3/5)$: $\sin B=3/5,\ \cos B=4/5$.
$\sin(A-B)=\sin A\cos B-\cos A\sin B=\dfrac{12}{13}\cdot\dfrac{4}{5}-\dfrac{5}{13}\cdot\dfrac{3}{5}=\dfrac{48}{65}-\dfrac{15}{65}=\dfrac{33}{65}$... Hmm, but let me check $\cos(A-B)$: $=\cos A\cos B+\sin A\sin B=\dfrac{5}{13}\cdot\dfrac{4}{5}+\dfrac{12}{13}\cdot\dfrac{3}{5}=\dfrac{20+36}{65}=\dfrac{56}{65}$.
So $A-B=\cos^{-1}(56/65)=\pi/2-\sin^{-1}(56/65)$. Answer: $\dfrac{\pi}{2}-\sin^{-1}\!\left(\dfrac{56}{65}\right)$.
\(\text{O}^{2-}(Z=8) > \text{F}^-(Z=9) > \text{Na}^+(Z=11) > \text{Mg}^{2+}(Z=12) > \text{Al}^{3+}(Z=13)\)
More protons = stronger pull on same electron cloud = smaller radius. There is a steady significant decrease across the series. No increase occurs — all species have the same number of electrons but increasing nuclear charge.
A company has: Ordinary shares $1.00 each: $200,000; Share premium: $80,000; Revenue reserves: $160,000. Changes in order: (1) One-for-one bonus issue; (2) Rights issue of 100,000 shares at $1.40 each. Company wishes to maximise dividends. What are the resulting balances?
Option A is correct.
Bonus issue (200,000 new shares @ $1): Use share premium $80,000 first, then revenue reserves $120,000.
After: Shares $400,000 | Share premium $0 | Revenue reserves $40,000
Rights issue (100,000 @ $1.40): $100,000 to share capital, $40,000 to share premium.
Final: Shares $500,000 | Share premium $40,000 | Revenue reserves $40,000
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