Trig Fcns part 4: value of sin^3(-pi/2) + 2cos^2(pi/4), etc

[Louise Johnson]

hello I have three more questions to be checked. Hopefully I am getting better at this.
Thanks
Louise

Find the value of sin^3 (-pi/2)+2cos^2 pi/4
Answer is 2 I had the sqrt of 1 + 1 which is 2

The graph f(x)=-3 sin x What is the period and range?Answer Period = 2pi/3 and Range [-3,3]

Sketch the graph g(x) = |cos pi x |
State the period and zero's of this functionThis one I am having real problems with. I have graphed it on my calculator using the absolute and it looks like a bunch of scribbles that don't touch the x axis.
Answer Period 2pi with no zero's

 

[skeeter]

Re: Trig Circular Functions part 4

hello I have three more questions to be checked. Hopefully I am getting better at this.
Thanks
Louise

Find the value of sin^3 (-pi/2)+2cos^2 pi/4
Answer is 2 I had the sqrt of 1 + 1 which is 2

no ... (-1)³ + 2(1/2) = 0

The graph f(x)=-3 sin x What is the period and range?Answer Period = 2pi/3 and Range [-3,3]

period is 2pi ... range is correct

Sketch the graph g(x) = |cos pi x |
State the period and zero's of this functionThis one I am having real problems with. I have graphed it on my calculator using the absolute and it looks like a bunch of scribbles that don't touch the x axis.
Answer Period 2pi with no zero's

period is 1, zeros at x = (2k+1)/2 where k is an integer

 

[Louise Johnson]

Thanks Skeeter
I see my error in the first question taking the sqr instead of -1^3.
Question two I guess I thought the -3 was the period not the range ...At least I will be able to see that from now on. Glad I got the Range correct!
The final question I am still somewhat baffled with. I will definately have to do some more investigating.

Thank you for your help !
Its really appreciated!
Louise