Wednesday, April 30, 2014

Compute the integral of sin x/(1+cos x)^0.5.

We'll re-write the denominator of the
fraction:


(1+cos x)^0.5 = sqrt(1+cos
x)


You'll have to substitute the expression within brackets
by another variable.


Let 1 + cos x =
t


We'll differentiate both
sides:


-sin x dx = dt => sin x dx =
-dt


We'll evaluate the
integral:


`int` sin xdx/sqrt(1+cos x) = `int` -dt/sqrt
t


`int` -t^(-1/2)*dt = - t^(-1/2 + 1)/(-1/2 + 1) +
C


`int` -t^(-1/2)*dt = - t^(1/2)/(1/2) +
C


`int` -t^(-1/2)*dt = - 2 sqrt t +
C


`int` sin xdx/sqrt(1+cos x) = -2 sqrt (1 +
cos x) + C

No comments:

Post a Comment

What is the meaning of the 4th stanza of Eliot's Preludes, especially the lines "I am moved by fancies...Infinitely suffering thing".

A century old this year, T.S. Eliot's Preludes raises the curtain on his great modernist masterpieces, The Love...