Live practice

Translate every condition into an equation and retain exact values throughout the straight-line calculation.

The last line satisfies the original conditions and supplies every requested part.

Write 0.99=1−0.01 and neglect terms of order 10⁻⁶ and smaller.

\[\begin{aligned}n(A\times B) &= 3\cdot2\\&= 6\end{aligned}\]. A relation is any subset of \(A\times B\); a six-element set has \(2^6\) subsets.

\(F=BIl\sin\theta\). It is maximum when \(\sin\theta=1\), that is, when current is perpendicular to the magnetic field.

Maximum: all series, \[\begin{aligned}R &= 4+8+12+24\\&= 48\end{aligned}\] Ω. Minimum: all parallel, \[\begin{aligned}\frac{1}{R} &= \frac{1}{4}+\frac{1}{8}+\frac{1}{12}+\frac{1}{24}\\&= \frac{1}{2}\end{aligned}\], so \(R=2.00\) Ω.

By Cartesian convention, a concave mirror has negative focal length. A concave/diverging lens also has negative focal length. Therefore both are concave.

Each cycle, oestrogen and progesterone thicken the uterine lining in preparation for implantation. If the released ovum is not fertilised, the corpus luteum regresses and hormone levels fall. The thickened lining can no longer be maintained, so it breaks down and is discharged with blood and the unfertilised ovum.

Receptors detect changes such as light, sound, pressure, temperature, chemicals and pain and convert them into nerve impulses. Failure causes loss or distortion of the corresponding sense. A person may not see or hear hazards, smell smoke, maintain balance or feel damaging heat and injury. Without protective sensations, tissue damage may occur unnoticed.

Phloem translocation moves mainly sucrose from a source, such as a leaf, to sinks such as roots, fruits or growing buds. Companion cells use ATP to load sucrose into sieve tubes. Water enters from xylem by osmosis, raising pressure. This pressure gradient drives mass flow to a sink, where sugar is unloaded; water can return to xylem.