Thread: Domain & range of trig function

1. Domain & range of trig function

need some help with this one guys..

y=2sin(3x + pi) -1

2. First of all use the formula $\sin(\pi+x)=-\sin x$.

Then $y=-2\sin 3x-1$

The domain is $\mathbb{R}$.

We have $-1\leq\sin 3x\leq 1\Rightarrow -2\leq -2\sin 3x\leq 2\Rightarrow -3\leq -2\sin 3x-1\leq 1$

So the range is $[-3,1]$

3. thanks a lot bro, btw, does the R in the domain mean all rea numbers?

4. You got it. The fancy "R" does, indeed, mean The Real Numbers. Guess what a fancy "N" means?