How do I solve the integral int_1^9 sqrt(x^2+4)dx

[devanlevin]

how do i integrate this equation, ie an equation with a complex function- sqared number inside sqr root

integrate from 1-9

$$\int$$$$\sqrt{x^2 +4}$$

what can i substitute?

 

[dirk_mec1]

$$2 tan(x)$$

 

[devanlevin]

how so??