Integration (AL) (20 marks)

2009-12-10 9:25 pm
Integrate y where
y=(x^2+1)^(1/2)
Please give presentation step by step. Thank you.
(20 marks)

回答 (1)

2009-12-11 4:10 am
✔ 最佳答案
Let x = sin@

Then, dx = cos@d@

y = (x^2 + 1)^1/2

S y dx

= S (x^2 + 1)^1/2 dx

= S [sin^2@ + 1]^1/2 cos@ d@

= S (cos^2@)^1/2 cos@ d@

= S cos^2@ d@

= S [(1 + cos2@)/2] d@

= @/2 + sin2@ / 4 + C

= 1/2 arcsin x + 2sin@cos@ / 4 + C

= 1/2 arcsin x + x(1 - x^2)^1/2 / 2 + C

where C is a constant
參考: Physics king


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