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# Trigi v2 watch

1. Solve the following equation for , in the interval :

With this I got 2 of the solutions.

However, apparently & are solutions to?

What did I do wrong?
2. (Original post by Naruke)
Solve the following equation for , in the interval :

With this I got 2 of the solutions.

However, apparently & are solutions to?

What did I do wrong?
You cannot divide by because you do not know what it is equal to - it could be equal to zero.

Try expanding the brackets on the right and then bringing everything on one side of the equation.
3. (Original post by MathQ123)
You cannot divide by because you do not know what it is equal to - it could be equal to zero.

Try expanding the brackets on the right and then bringing everything on one side of the equation.
Thanksssssssssssssssss
4. (Original post by Naruke)
Thanksssssssssssssssss
It's kind of analogous to when you have , you'd normally move everything to one side to get: which gives you two solutions. You recognise that it is folly to do , right?

Same thing here, never cancel trigonometric functions, always factorise them out. So in this case:

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