A-Level Maths OCR B (MEI) H640

7: Trigonometry

#7.1

Know how to solve right-angled triangles using trigonometry.

#7.10

Know and be able to use exact values of sinθ\sin{θ}, cosθ\cos{θ} and tanθ\tan{θ} for θ=0,π6,π4,π3θ = 0, \dfrac{\pi}{6}, \dfrac{\pi}{4}, \dfrac{\pi}{3}, π\pi and multiples thereof and sinθ\sin{θ}, cosθ\cos{θ} for θ=π2θ = \dfrac{\pi}{2} and multiples thereof.

#7.11

Understand and use the definitions of the functions arcsin\arcsin, arccos\arccos and arctan\arctan, their relationship to sin\sin, cos\cos and tan\tan, their graphs and their ranges and domains.

#7.12

Understand and use the definition of a radian and be able to convert between radians and degrees.

#7.13

Know and be able to find the arc length and area of a sector of a circle, when the angle is given in radians.

The results s=rθs = rθ and A=12r2θA = \dfrac{1}{2}r^2θ where θθ is measured in radians.

#7.14

Understand and use the standard small angle approximations of sine, cosine and tangent.

sinθ=θ\sin{θ} = θ, cos1θ22\cos{1-\dfrac{θ^2}{2}}, tanθ\tan{θ} where θθ is in radians.

#7.15

Understand and use the definitions of the sec\sec, cosec\cosec and cot\cot functions.

Including knowledge of the angles for which they are undefined.

#7.16

Understand relationships between the graphs of the sin\sin, cos\cos, tan\tan, cosec\cosec, sec\sec and cot\cot functions.

Including domains and ranges.

#7.17

Understand and use the relationships tan2θ+1=sec2θ\tan^2{θ} + 1 = \sec^2{θ} and cot2θ+1=cosec2θ\cot^2{θ} + 1 = \cosec^2{θ}.

#7.18

Understand and use the identities for sin(θ±ϕ)\sin{(θ \pm ϕ)}, cos(θ±ϕ)\cos{(θ \pm ϕ)}, tan(θ±ϕ)\tan{(θ \pm ϕ)}.

*Includes understanding geometric proofs. The starting point for the proof will be given.

Excludes: Proofs using de Moivre’s theorem will not be accepted.*

#7.19

Know and use identities for sin2θ\sin{2θ}, cos2θ\cos{2θ}, tan2θ\tan{2θ}.

Includes understanding derivations from sin(θ±ϕ)\sin{(θ \pm ϕ)}, cos(θ±ϕ)\cos{(θ \pm ϕ)}, tan(θ±ϕ)\tan{(θ \pm ϕ)}. cos2θcos2θsin2θ\cos{2θ} ≡ \cos^2{θ} - \sin^2{θ}cos2θ2cos2θ1\cos{2θ} ≡ 2\cos^2{θ} - 1cos2θ12sin2θ\cos{2θ} ≡ 1 - 2\sin^2{θ}

#7.2

Be able to use the definitions of sinθ\sin{θ}, cosθ\cos{θ} and tanθ\tan{θ} for any angle.

By reference to the unit circle, sinθ=y\sin{θ}=y, cosθ=x\cos{θ}=x, tanθ=yx\tan{θ}=\dfrac{y}{x}.

#7.20

Understand and use expressions for acosθ±bsinθa \cos{θ} \pm b \sin{θ} in the equivalent forms Rsin(θ±α)R\sin{(θ \pm α)} and Rcos(θ±α)R\cos{(θ \pm α)}.

Includes sketching the graph of the function, finding its maximum and minimum values and solving equations.

#7.21

Use trigonometric identities, relationships and definitions in solving equations.

#7.22

Construct proofs involving trigonometric functions and identities.

#7.23

Use trigonometric functions to solve problems in context, including problems involving vectors, kinematics and forces.

The argument of the trigonometric functions is not restricted to angles.

#7.3

Know and use the graphs of sinθ\sin{θ}, cosθ\cos{θ} and tanθ\tan{θ} for all values of θθ, their symmetries and periodicities.

*Stretches, translations and reflections of these graphs. Combinations of these transformations.

Notation: Period*

#7.4

Know and be able to use the exact values of sinθ\sin{θ} and cosθ\cos{θ} for θ=0°,30°,45°,60°,90°θ = 0°, 30°, 45°, 60°, 90° and the exact values of tanθ\tan{θ} for θ=0°,30°,45°,60°θ = 0°, 30°, 45°, 60°.

#7.5

Know and be able to use the fact that the area of a triangle is given by 12absinC\dfrac{1}{2}ab\sin{C}.

#7.6

Know and be able to use the sine and cosine rules.

Use of bearings may be required.

#7.7

Understand and be able to use tanθ=sinθcosθ\tan{θ} = \dfrac{\sin{θ}}{\cos{θ}}

e.g. solve sinθ=3cosθ\sin{θ} = 3\cos{θ} for 0°θ360°0° \le θ \le 360°.

#7.8

Understand and be able to use the identity sin2θ+cos2θ=1\sin^2{θ} + \cos^2{θ} = 1.

e.g. solve sin2θ=cosθ\sin^2{θ} = \cos{θ} for 0°θ360°0° \le θ \le 360°.

#7.9

Be able to solve simple trigonometric equations in given intervals and know the principal values from the inverse trigonometric functions.

*e.g. sinθ=0.5\sin{θ} = 0.5, in [0°,360°]    θ=30°,150°[0°, 360°] \iff θ = 30° ,150° Includes equations involving multiples of the unknown angle e.g. sin2θ=3cos2θ\sin{2θ} = 3\cos{2θ}. Includes quadratic equations.

Notation: arcsinx=sin1x\arcsin{x} = \sin^{-1}{x}arccosx=cos1x\arccos{x} = \cos^{-1}{x}arctanx=tan1x\arctan{x} = \tan^{-1}{x}

Excludes: General solutions.*

6
Sequences and series
8
Exponentials and logarithms