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CanadaON
Grade 12

Evaluate trig expressions using angle sum and difference identities

Interactive practice questions

Given that $\sin A=\frac{24}{25}$sinA=2425 and $\cos B=\frac{20}{29}$cosB=2029, find the exact value of:

a

$\sin\left(A+B\right)$sin(A+B)

b

$\cos\left(A-B\right)$cos(AB)

Easy
10min

Given that $\sin A=\frac{24}{25}$sinA=2425 and $\tan B=\frac{20}{21}$tanB=2021, where $A$A and $B$B are acute angles, find the exact value of:

Easy
11min

Find the value of $\sin20^\circ\cos40^\circ+\sin40^\circ\cos20^\circ$sin20°cos40°+sin40°cos20° in exact form.

Easy
1min

Using the expansion of $\cos\left(A+B\right)$cos(A+B), find the exact value of $\cos75^\circ$cos75°. Express the value in rationalised form.

Easy
3min
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Outcomes

12F.B.3.2

Explore the algebraic development of the compound angle formulas, and use the formulas to determine exact values of trigonometric ratios

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