Evaluate  as the limit of a sum. from Mathematics Integrals

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsShort Answer Type

31.

Evaluate integral subscript straight a superscript straight b cosx space dx as the limit of a sum.

98 Views

 Multiple Choice QuestionsLong Answer Type

Advertisement

32.

Evaluate integral subscript straight a superscript straight b space sin squared straight x space dx as the limit of a sum.


Comparing integral subscript straight a superscript straight b space sin squared straight x space dx space space with space integral subscript straight a superscript straight b straight f left parenthesis straight x right parenthesis space dx comma space we space get comma
                       straight f left parenthesis straight x right parenthesis space equals space sin squared straight x equals fraction numerator 1 minus cos space 2 straight x over denominator 2 end fraction space equals space 1 half left parenthesis 1 minus cos space 2 straight x right parenthesis
Now,        integral subscript straight a superscript straight b straight f left parenthesis straight x right parenthesis space dx space equals space Lt with straight h rightwards arrow 0 below space straight h left square bracket straight f left parenthesis straight a right parenthesis plus straight f left parenthesis straight a plus straight h right parenthesis plus straight f left parenthesis straight a plus 2 straight h right parenthesis plus.... plus straight f left parenthesis straight a plus stack straight n minus 1 with bar on top space straight h right parenthesis right square bracket
therefore           integral subscript straight a superscript straight b sin squared straight x space dx space equals space Lt with straight h rightwards arrow 0 below straight h over 2 left square bracket left parenthesis 1 minus cos space 2 straight a plus left curly bracket 1 minus cos space 2 space left parenthesis straight a plus straight h right parenthesis right curly bracket
                                               plus left curly bracket 1 minus cos 2 left parenthesis straight a plus 2 straight h right parenthesis right curly bracket plus.... plus right curly bracket space left curly bracket 1 minus cos space 2 left parenthesis straight a plus stack straight n minus 1 with bar on top space straight h right parenthesis right curly bracket right square bracket
equals space Lt with straight h rightwards arrow 0 below straight h over 2 left square bracket straight n minus left curly bracket cos 2 straight a plus cos 2 left parenthesis straight a plus straight h right parenthesis plus cos 2 left parenthesis straight a plus 2 straight h right parenthesis plus... plus cos 2 left parenthesis straight a plus stack straight n minus 1 with bar on top space straight h right parenthesis right curly bracket right square bracket
space space equals space Lt with straight h rightwards arrow 0 below space straight h over 2 open square brackets straight n minus fraction numerator cos space open curly brackets begin display style fraction numerator 2 straight a plus 2 straight a plus 2 left parenthesis straight n minus 1 right parenthesis straight h over denominator 2 end fraction end style close curly brackets sin open parentheses straight n begin display style fraction numerator 2 straight h over denominator 2 end fraction end style close parentheses over denominator sin open parentheses begin display style fraction numerator 2 straight h over denominator 2 end fraction end style close parentheses end fraction close square brackets

   equals space Lt with straight h rightwards arrow 0 below straight h over 2 open square brackets straight n minus fraction numerator cos left parenthesis 2 straight a plus left parenthesis straight n minus 1 right parenthesis space straight h right curly bracket space sin space straight n space straight h over denominator sin space straight h end fraction close square brackets space equals space Lt with straight h rightwards arrow 0 below 1 half open square brackets straight n space straight h minus fraction numerator cos left curly bracket 2 straight a plus left parenthesis nh minus straight h right parenthesis right curly bracket space sin space nh over denominator begin display style fraction numerator sin space straight h over denominator straight h end fraction end style end fraction close square brackets
equals space Lt with straight h rightwards arrow 0 below 1 half open square brackets straight b minus straight a minus fraction numerator cos left curly bracket 2 straight a plus left parenthesis straight b minus straight a minus straight h right parenthesis right curly bracket space sin left parenthesis straight b minus straight a right parenthesis over denominator begin display style fraction numerator sin space straight h over denominator straight h end fraction end style end fraction close square brackets

space space equals space 1 half open square brackets straight b minus straight a minus fraction numerator cos left parenthesis 2 straight a plus straight b minus straight a minus 0 right parenthesis space sin left parenthesis straight b minus straight a right parenthesis over denominator 1 end fraction close square brackets space equals space 1 half left square bracket straight b minus straight a minus cos left parenthesis straight a plus straight b right parenthesis space sin left parenthesis straight b minus straight a right parenthesis right square bracket

   equals space 1 half open square brackets left parenthesis straight b minus straight a right parenthesis space minus space 1 half 2 space cos left parenthesis straight b plus straight a right parenthesis space sin left parenthesis straight b minus straight a right parenthesis right square bracket close square brackets
equals space 1 half open square brackets left parenthesis straight b minus straight a right parenthesis minus 1 half left parenthesis sin space 2 straight b space minus space sin space 2 straight a right parenthesis close square brackets
equals space 1 half open square brackets left parenthesis straight b minus straight a right parenthesis plus left parenthesis sin space straight a space cos space straight a space minus space sin space straight b space cos space straight b right parenthesis close square brackets
  
                                                     

 

98 Views

Advertisement

 Multiple Choice QuestionsShort Answer Type

33.

Evaluate the following definite integrals as limit of sums.
integral subscript 2 superscript 3 straight x squared dx

217 Views

34.

Evaluate the following definite integral
integral subscript negative 1 end subscript superscript 1 left parenthesis straight x plus 1 right parenthesis space dx

156 Views

Advertisement
35.

Evaluate the following definite integral
integral subscript 2 superscript 3 1 over straight x dx


95 Views

36.

Evaluate the following definite integral
integral subscript 0 superscript 8 straight x to the power of 5 over 3 end exponent dx



98 Views

37.

Evaluate the following definite integral
integral subscript 0 superscript 4 straight x to the power of 1 half end exponent dx





108 Views

38.

Evaluate the following definite integral
integral subscript 0 superscript 4 open parentheses straight x plus straight x to the power of 3 over 2 end exponent close parentheses dx






148 Views

Advertisement
39.

Evaluate the following definite integral
integral subscript 0 superscript straight pi space tanx space dx







105 Views

40.

Evaluate the following definite integral
integral subscript 0 superscript straight pi over 2 end superscript space cos space 2 straight x space dx








86 Views

Advertisement