Trig Substitution

Question 1

Expression: sqrt(a^2-x^2)

Answer 1

Identity: 1-sin^2(t)=cos^2(t)

x=asint

Question 2

Expression: sqrt(a^2+x^2)

Answer 2

Identity: 1+tan^2(t)=sec^2(t)

x=atant

Question 3

Expression: sqrt(x^2 - a^2)

Answer 3

Identity: sec^2(t)-1=tan^2(t)

x=asect