Posted by **Lucy** on Saturday, August 30, 2008 at 8:38pm.

State the period and phase shift of the function y=-4tan(1/2x + 3pi/8)

a) 2pi, -3pi/4

b) pi, 3pi/8

c) 2pi, 3pi/8

d) pi, -3pi/8

Answer: d

2) What is the equation for the inverse of y=cos x+3:

a) y=Arccos(x+3)

b) y=Arccos x-3

c) y=Arccos x+3

d) y=Arccos(x-3)

Answer:d

Thanks for your help

- Pre-Calculus-check answers -
**Reiny**, Saturday, August 30, 2008 at 11:22pm
in y=-4tan(1/2x + 3pi/8)

y = -4 tan (1/2)[x + 3pi/4]

so the period is 2pi/(1/2) = 4pi which is none of your choices.

Did you type your questions or answers correctly??

the phase shift would be 3pi/4 radians to the left.

2)

the inverse of y = cos x+3 is x = cos y+3

then cos y = x-3

and y = arccos(x-3)

- Pre-Calculus-check answers -
**Lucy**, Saturday, August 30, 2008 at 11:59pm
I double checked my typing on the first problem and everything was entered correctly.

- Pre-Calculus-check answers -
**Reiny**, Sunday, August 31, 2008 at 12:29am
then the book is wrong

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