Posted by **Christina** on Tuesday, August 14, 2012 at 9:09pm.

I posted this question before but accidentally typed in the wrong values! Please help, I just need to know the basic formula my book didn't provide any examples.

For the function y = -2sin(x-(pi/3)) between x = 0 and x = 2pi : (6 marks)

For what value(s) of x does y have its maximum value?

For what value(s) of x does y have its minimum value?

For what value(s) of x does y=1?

- Math -
**Reiny**, Tuesday, August 14, 2012 at 11:05pm
dy/dx = -2cos(x - π/3)

at a max/min , dy/dx = 0

-2cos(x-π/3) = 0

cos(x-π/3) = 0

I know that cos π/2 = 0 or cos 3π/2 = 0

so x - π/3 = π/2 or x - π/3 = 3π/2

x = 5π/6 or x = 11π/6 , (150° or 330°)

when x = 5π/6 , y = -2sin(π/2) = -2

when x = 11π/6 , y = -2sin(3π/2) = +2

so the function has a maximum value of 2 when x = 11π/3

and a minimum value of -2 when x = 5π/6

when y = 1

-2sin(x-π/3) = 1

sin(x-π/3) = -1/2

I know sin 210° = -1/2 and sin 330°=-1/2

which is 7π/6 or 11π/6

x-π/3 = 7π/6 or x-π/3=11π/6

**x = 3π/2 or x = 13π/6**

## Answer this Question

## Related Questions

English - What are examples of traditional values and opposing forces of those ...

Software - Excel - Hi, Im doing my maths coursework andI need to type in a ...

Math - Use a graphing utility to graph the function. Then use the trace or table...

Math - Use a graphing utility to graph the function. Then use the trace or table...

Microsoft Excel 2007 - I think that I already typed this in, but forgot to click...

Math - Hi, I am getting very frustrated. I am doing an online homework for ...

Forgot my book, need science help!! - Please help me I have a whole section to ...

Math 2nd question - Express as a single sine or cosine function (note: this is ...

social 10 COULD SOMEONE PLEASE HELP ME! - Historical Globalization & IMPERIALISM...

Health Repost - Earlier i posted a question about brushing teeth. I just wanted ...