Further Calculus

Question 1

What substitution should I use when integrating something in the form of:
Square root(1-x²)

Answer 1

The substitution is x=sin(u)

Question 2

What substitution should I use when integrating something in the form of:
1/(1+x²)

Answer 2

Choose x=tan(u)

Question 3

What substitution should I use when integrating something in the form of:
Square root(a²-x²) where a is an integer e.g 25

Answer 3

x=sin(u)

Question 4

What substitution should I use when integrating something in the form of:
a²+x² where a is an integer

Answer 4

x=tan(u)