I have two quick questions about basic trig.My first question is asking to find period, amplitude, and phase shift of a function written as

f(x) = -cos(pi(x - 0.1))

Can i write the function as

f(x) = -cos(pi x - 0.1)?

Mr F says: No. .
Also I was asked to find the values of x between [0, 2pi] of the following equation

2sin^2 = 1

When i solve this equation I get

sinx = 1/ root 2

Mr F says: .
There is no special angle

Mr F says: Yes there is.
or this solution so would I use a decimal approximation?

Mr F says: No. See above.
Thanks for any help