Find the exact value of sin 30 ° - sin 45 ° cos 45 ° i dnt unnderstand how u find the value

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- Jun 8th 2008, 04:34 PMmissjkyangles and trigonometic functions
Find the exact value of sin 30 ° - sin 45 ° cos 45 ° i dnt unnderstand how u find the value

- Jun 8th 2008, 05:00 PMMathstud28
- Jun 8th 2008, 05:03 PMmasters
- Jun 8th 2008, 05:06 PMmissjky
[quote=masters;155321]

thanks so much and also the exact value of cos http://ce.byu.edu/courses/hs/9990640.../TRIG41-52.gif - Jun 8th 2008, 05:07 PMMathstud28
- Jun 8th 2008, 05:09 PMmissjky
- Jun 8th 2008, 05:25 PMo_O

I don't know what is meant by 'standard position' but I'm assuming that the angle is restricted to Quadrant I.

If you recall the definition that , then you can draw a right angled triangle with a base of 12 and a height of 5 with as your angle.

Recall that . We already have the 'opposite' side, i.e. 5. We just need the hypotenuse which you can easily calculate with Pythagoras' Theorem. - Jun 8th 2008, 05:30 PMmissjky
- Jun 8th 2008, 05:33 PMmissjky
- Jun 8th 2008, 05:36 PMo_O
Do you know what and stand for in terms of a triangle? You should be able to figure it out.

Here's a diagram to help illustrate what I'm trying to say. Solve for**h**and you should be able to find - Jun 8th 2008, 05:47 PMmissjky
- Jun 8th 2008, 05:47 PMo_O
(Yes)