a few more trig questions that i need help with sin(x)(sin(x)-1)
How do I solve this

Question

a few more trig questions that i need help with sin(x)(sin(x)-1)
How do I solve this

mathstudent55 · Answer

What is that? 
Is it an equation?
Where is the equal sign?

cutiecomittee123 · Answer

oh yeah it is equal to 0
it should be 
sin(x)(sin(x)-1)=0

mathstudent55 · Answer

The algebraic part of this equation is similar to:

y(y - 1) = 0

This is a quadratic equation that has already been factored, so just set each factor equal to zero to find y.

In my example, you'd continue:

y = 0 or y - 1 = 0

y = 0 or y = 1

Do you understand my example?

mathstudent55 · Answer

Your equation is similar to my example in the algebra part, but then you need to continue with the trig part.

cutiecomittee123 · Answer

so just multiply it out

mathstudent55 · Answer

No. Just use the zero product rule:

$\sin x (\sin x-1)=0$

You have a product equaling zero.
A product is only equal to zero if one of its factors equal zero.
That is the zero product rule.

Set each factor equal to zero and solve each one as an equation.

$\sin x = 0$   or  $\sin x - 1 = 0$

cutiecomittee123 · Answer

i am kinds stuck though 
sin(x)^2-sin(x)-1=0 is what i get when i do that

cutiecomittee123 · Answer

oh i see it okay

mathstudent55 · Answer

What you did is as if you got a factored quadratic equation, and instead of setting each factor equal to zero, you multiplied it out.

cutiecomittee123 · Answer

okay so sin(x)=0 and sin(x)=1

mathstudent55 · Answer

Some of the work was already done for you.
You didn't have to factor it.
Now set each factor equal to zero and solve each factor as an equation.

mathstudent55 · Answer

Exactly.
Where the sine = 0?

mathstudent55 · Answer

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cutiecomittee123 · Answer

at 0 and pi

mathstudent55 · Answer

Great.
Now the second equation.
$\sin x = 1$

mathstudent55 · Answer

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