How do you simplify Cos[(pi/2)-x]/sin[(pi/2)-x] ?
1 Answer
Feb 27, 2016
tanx
Explanation:
Expand numerator and denominator using appropriate
color(blue) " Addition formulae "
• cos(A ± B ) = cosAcosB ∓ sinAsinB
• sin(A ± B ) = sinAcosB ± cosAsinB
color(red) " Numerator "
cos( pi/2 - x ) = cos(pi/2)cosx + sin(pi/2)sinx now
cos(pi/2) = 0 " and " sin(pi/2) = 1 simplifies to : 0 + sinx = sinx
color(orange) " Denominator "
sin(pi/2 - x ) = sin(pi/2)cosx + cos(pi/2)sinx simplifies to : cosx + 0 = cosx
rArr cos(pi/2 -x )/sin(pi/2 -x) = sinx/cosx = tanx