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Integral problem

  • Thread starter jnimagine
  • Start date
  • #1
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suppose that f is continuous and (integral]0->2 f(x)dx = 6. Then (integral]0 -> pi/2 f(2sinb)cosbdb=?

ok.... i'm totally lost here... how do u solve this without knowing what f(x) is..????
 

Answers and Replies

  • #2
dx
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Do you know how to change variables in integrals? In the second integral, change variables to y = 2sinb.
 
  • #3
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Do you know how to change variables in integrals? In the second integral, change variables to y = 2sinb.
so if y = 2sinb then dy = 2cosbdb hence 1/2(integral]0->2f(y)dy) = 1/2(6) = 3
Is this the answer?
 
  • #4
dx
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Yes.
 

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