Trigonometry – Solving Trigonometric Equations

Now, time to tie it all together, and say good-bye to the Commander-in-TEACH, President ObaMATH. 'Twas a good run, showing the world his hidden math talents, specifically regarding trigonometric identities. In this series finale, we solve trig equations, using everything we know to do by now: factoring, combining like terms, and applying trig identities. Thank you for supporting this campaign of learning. YAY MATH!

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[derrickseo]

All the kids have grown and Matured also i miss their voices! So shocking yet kewl

[matthswiz]

i enjoyed this video lesson, it is among those videos that motivated me to release mine....
you should view it, ti is a wonderful lesson

[BatMandor]

the last problem can be generalized to pi*n... sin(theta) is 0 at 180 as well....

[countotuscany]

Oh man, what the hell would we do without yaymath?

[whalestailz]

2sincos = 2sin is the equivalent of saying 2(x)(y) = 2(x)
It's simply not true, you're leaving out a factor.
sin (2theta) does equal 2 sin(theta)*cos(theta), , but neither of them equal 2* sin(theta) as it is written here... so you cannot use it to equate those two identities.

It's like he threw it in there to be able to equate something easier for the kids to solve, and less work for himself, but it is simply not correct lol.


These are a list of valid identities:

[blastydog]

as a Grade 9, I don't understand this language