-->

Integrals

Question
CBSEENMA12032577

Evaluate integral subscript negative 1 end subscript superscript 1 sin to the power of 5 straight x space cos to the power of 4 straight x space dx

Solution

Comparing integral subscript negative 1 end subscript superscript 1 space sin to the power of 5 straight x space cos to the power of 4 straight x space dx space with space integral subscript negative 1 end subscript superscript 1 space straight f left parenthesis straight x right parenthesis space dx comma space space we space get
f (x) = sin5 x cos4 x
Now f (–x) = sin5 (–x) cos4 (–x) = – sinx cos4 x = – f (x)
∴ f (x) is an odd function
therefore space space space space straight I space equals space 0                     [integral subscript negative straight a end subscript superscript straight a straight f left parenthesis straight x right parenthesis space dx space equals space 0 space space if space straight f left parenthesis straight x right parenthesis is an odd function]
therefore space space space integral subscript negative 1 end subscript superscript 1 space sin to the power of 5 straight x space cos to the power of 4 straight x space dx space equals space 0

Some More Questions From Integrals Chapter