ques=?Sin to the power3(2x+1) dx We know sin to the power 3 A= (3sinA-sin3A)/4 So Sin to the power3(2x+1) = (3sin(2x+1)-sin3(2x+1))/4 => ?(3sin(2x+1)-sin3(2x+1))/4 dx => ?(3sin(2x+1)-sin(6x+3))/4 dx => 1/4 ?(3sin(2x+1)-sin(6x+3))dx => 1/4 (-3/2 cos(2x+1)+ 1/6 cos(6x+3)) +C => 1/4 (1/6 cos(6x+3) -3/2 cos(2x+1)) +C can't we solve the ques as above instead of as you have solved in ncert textbook sol.(Ex=7.3, Q-4)

Asked by Archana | 2nd Feb, 2014, 06:43: AM

Expert Answer:

Dear Archana

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
 
You can solve this problem in any method you prefer.
 
Trigonometric functions can reduce to different forms and therefore your answer should be the most reduced form.
 
It depends on the question also.
 
If it is specified that this question has to be solved using reduction formula, then you need to solve that question in that method only.
 
Regards

Topperlearning Team.

Answered by  | 3rd Apr, 2014, 12:59: PM

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