Solve for a when f(a)=2=1/(sqr(1-a)) Multiply both sides of the equation by sqr(1-a). Thsi implies,
2sqr(1-a)=1 Square both sides.
4(1-a)=1
4-4a=1
-4 -4
-4a=-3 a=3/4
f(1-a)=1/sqr(1-(1-a))=1/sqr(1-1+a)=1/sqr(a)=1/sqr(3/4)=1/√3/2=2/√3
Edward, it is good to get into the habit to get rid of the radical in the denominator of the fraction. Multiply both the numerator and denominator by √3 in which is.
2/√3*√3/√3=2√3/3=2/3*√3. Note: 2/3*√3 seems easier to see the answer then 2/√3.