Trigonometry (1 Viewer)

nsbrando · Jun 25, 2012

find exact value

cos30 cos60 - sin30 sin60

zeebobDD · Jun 25, 2012

Fus Ro Dah · Jun 25, 2012

You sure are asking a lot of exact value questions!

$\frac{\sqrt 3}{2} \times \frac{1}{2} - \frac{1}{2} \times \frac{\sqrt 3}{2} = 0$

Another way of doing this is recognising the Compound Angle formula for cos(a+b), which gives us cos(30+60)=cos(90), which is equal to 0.

Shadowdude · Jun 25, 2012

Fus Ro Dah said:
You sure are asking a lot of exact value questions!

$\frac{\sqrt 3}{2} \times \frac{1}{2} - \frac{1}{2} \times \frac{\sqrt 3}{2} = 0$

Another way of doing this is recognising the Compound Angle formula for cos(a+b), which gives us cos(30+60)=cos(90), which is equal to 0.

Compound angles are a 3u topic, though.

Trigonometry (1 Viewer)

nsbrando

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Fus Ro Dah

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Shadowdude

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