Where homework finally clicks.

Today3 sheets

Math

Limits & continuity

lim_{x \to 0} \frac{s i n x}{x} = 1

Chemistry

First-order kinetics

[A] = [A]_{0} e^{- k t}

Physics

Projectile range

R = \frac{v _{0}^{2} s i n 2 θ}{g}

+ 3 more subjects

Step-by-step guide

At the half-life, what fraction of

[A]

remains? Just the fraction.

Half of it.

Right. So set

[A] = [A]_{0} /2

and solve:

t_{1/2} = \frac{ln 2}{k}

Why ln 2?Next step