Question

If sin y = 9/c and tan y = 9/d what is the vaule of cos y

Answer 1

`\huge \purple { \boxed{\therefore \: \cos \: y = (d)/(c) }}`

Explanation:

`\because \: \tan \: y = ( \sin \: y)/( \cos \: y) \\ \\ \therefore \: \cos \: y = ( \sin \: y)/( \tan \: y) \\ \\ \therefore \: \cos \: y = ( (9)/(c) )/( (9)/(d) ) \\ \\ \therefore \: \cos \: y = (9)/(c) * (d)/(9) \\ \\ \huge \red{ \boxed{\therefore \: \cos \: y = (d)/(c) }}`