Summary OCR AS Mathematics (Trigonometric ratio)

OCR A-Level Mathematics
1.05 Trigonometry (Pt.1)




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, Trigonometric Ratios




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, 1 SINE, COSINE AND TANGENT
• From GCSE, you should already know what sine, cosine and tangent are…




𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒
𝑠𝑖𝑛𝜃 =
ℎ𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒
𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡
𝑐𝑜𝑠𝜃 =
ℎ𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒
𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒
𝑡𝑎𝑛𝜃 =
𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡

• To easily remember this, we have SOHCAHTOA:




S O H ine is pposite over ypotenuse




C A Hosine is djacent over ypotenuse




T O A angent is pposite over djacent


• We have some standard angles to remember:

30o 45o 60o
1 √2 √3
Sine
2 2 2
√3 √2 1
Cosine
2 2 2
√3 1
Tangent 𝑜𝑟 1 √3
3 √3




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