How to solve this identity? Thank you!

You need to prove that #cotx - coty = (sin(y-x))/(sinx * siny)#

Thank you very much!

1 Answer
Jim G.
Dec 8, 2017

#"see explanation"#

Explanation:

#"using the "color(blue)"trigonometric identities"#

#•color(white)(x)sin(y-x)=sinycosx-cosysinx#

#•color(white)(x)cotx=cosx/sinx#

#"consider the left side"#

#cotx-coty#

#=cosx/sinx-cosy/siny#

#=(cosxsiny-sinxcosy)/(sinxsiny)#

#=(sin(y-x))/(sinxsiny)#

#=" right side "rArr" verified"#

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