Trigonometry - Further trigonometric identities - angle sum and difference.
Test Yourself 1.
The results required for these further identities are:
sin (A ± B) = sin A cos B ± cos A sin B
cos (A + B) = cos A cos B - sinA sin B
Expanding terms. | Expand sin (2x + y). | Expand cos (2x - y). |
Expand tan (4α - 3β). | Expand and simplify tan (A + 45°). |
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Find the exact value of sin (75°) by expanding sin (30° + 45°) and simplifying with exact values. | Find the exact value of cos (105°) by expanding cos (60° + 45°) and simplifying with exact values. |
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Expand sin ((a+b) - c). | Expand cos ((3α + 2β)+ γ). | |
Expand cos (2θ + 60°). | Expand tan (x + 135°). | |
Simplifying. | cos 60°cos 30° - sin 60° sin 30°. | sin 60°cos 30° - cos 60° sin 30°. |
Simplify sin (2α + β) cosβ - cos (2α + β)sin (β) |
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Evaluating. | If , where 0 < β < α < 90°, evaluate
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Equations. | (i) Show that (ii) Hence find the solutions for tan 2x + tanx = 0 in the domain [0, 90°]. |