If sin(x) = 4cos(x), then what is (sin(x))*(cos (x))?

Answer 1

if sinx = 4cosx
sinx/cosx =4
tanx= 4 = 4/1

sketch a right-angled triangle with opposite 4 and adjacent 1
then r^2= 4^2 + 1^2
r = √17

then sinx = 4/√17 , cosx = 1/√17

sinxcosx = (4/√17)(1/√17) = 4/17