GCSE Maths OCR J560

6.02: Algebraic formulae

#6.02a

Formulate simple formulae and expressions from real-world contexts.

e.g. Cost of car hire at £50 per day plus 10p per mile. The perimeter of a rectangle when the length is 2 cm more than the width.

See, for example, Direct proportion, 5.02a, Inverse proportion, 5.02b, Growth and decay, 5.03a

#6.02b

Substitute positive numbers into simple expressions and formulae to find the value of the subject.

e.g. Given that v=u+atv = u + at, find vv when t=1t = 1, a=2a = 2 and u=7u = 7

Subsitute positive or negative numbers into more complex formulae, including powers, roots and algebraic fractions.

e.g. v=u2+2asv = \sqrt{u^2 + 2as} with u=2.1u = 2.1, s=0.18s = 0.18, a=9.8a = -9.8.

#6.02c

Rearrange formulae to change the subject, where the subject appears once only.

e.g. Make dd the subject of the formula c=πdc = \pi d.

Make xx the subject of the formula y=3x2y = 3x-2.

Rearrange formulae to change the subject, including cases where the subject appears twice, or where a power or reciprocal of the subject appears.

e.g. Make tt the subject of the formulae

(i)s=12at2s = \dfrac{1}{2}at^2

(ii) v=xtv = \dfrac{x}{t}

(iii) 2ty=t+12ty = t+1

Examples may include manipulation of algebraic fractions, 6.01g

#6.02d

Recall and use:

Circumference of a circle 2πr=πd2 \pi r = \pi d

Area of a circle πr2\pi r^2

Recall and use:

Pythagoras’ theorem a2+b2=c2a^2 + b^2 = c^2

Trigonometry formulae sinθ=oh\sin{\theta} = \dfrac{o}{h}, cosθ=ah\cos{\theta} = \dfrac{a}{h}, tanθ=oa\tan{\theta} = \dfrac{o}{a}

**Recall and use:

The quadratic formula x=b±b24ac2ax = \dfrac{−b±\sqrt{b^2−4ac}}{2a}

Sine rule asinA=bsinB=csinC\dfrac{a}{\sin{A}} = \dfrac{b}{\sin{B}} = \dfrac{c}{\sin{C}}

Cosine rule a2=b2+c22bccosAa^2 = b^2 + c^2 - 2bc\cos{A}

Area of a triangle 12absinC\dfrac{1}{2}ab\sin{C} **

#6.02e

Use:

v=u+atv = u + at

s=ut+12at2s = ut + \frac{1}{2}at^2

v2=u2+2asv^2 = u^2 + 2as

where aa is constant acceleration, uu is initial velocity, vv is final velocity, ss is displacement from position when t=0t = 0 and tt is time taken.

6.01
Algebraic expressions
6.03
Algebraic equations