1.

Show that `sin^(-1)(3/5)-sin^(-1)(8/17)=cos^(-1)(84/85)`

Answer» `sin^(-1)(3/5)=x and sin^(-1)(8/17)=y`
`3/5=sinx and 8/17=siny`
cosx=4/5 and cosy=15/17
cos(x-y)=cosxcosy+sinxsiny
=`(4/5)(15/17)+(3/5)(8/17)`
cos(x-y)=84/85
`x-y=cos^(-1)(84/85)`
`sin^(-1)(3/5)-sin^(-1)(8/17)=cos^(-1)(84/85)`
Hence proved


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