Question

prove that sin (47÷cos43)+(cos 43÷sin47)-4cos 45=0

Answer 1

$( \frac{ \sin47}{ \cos43 } )+ ( \frac{ \cos43 }{ \sin47 } ) - (4 \times \frac{1}{2} ) \\ ( \frac{ \sin(90 - 43) }{ \cos43 } ) + ( \frac{ \cos(90 - 47 ) }{ \sin47 } ) - 2 \\ \frac{ (\cos43 }{ \cos43 } ) + ( \frac{ \sin47 }{ \sin47 }) - 2 \\ 1 + 1 - 2 \\ 2 - 2 \\ 0 = 0$

Answer 2

it can't be cos45 it has to be (cos 45) ^2