PreCalculuscheck answers
posted by Lucy on .
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 x3
c) y=Arccos x+3
d) y=Arccos(x3)
Answer:d
Thanks for your help

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 = x3
and y = arccos(x3) 
I double checked my typing on the first problem and everything was entered correctly.

then the book is wrong

I am not surprised as I have found many errors thus far.
Thanks for helping