thanks in advance!
Since the numerator and denominator approach 0, use L'Hopital's rule and take the derivatives of the numerator and denominator. Also, it's pi, not pie.
lim (1 - tanx)/(sinx - cosx) =
x-> pi/4
lim -sec^2x/(cosx + sinx) = -(√2)^2/(√2/2 + √2/2) = -2/(√2) = -√2
Comments
Since the numerator and denominator approach 0, use L'Hopital's rule and take the derivatives of the numerator and denominator. Also, it's pi, not pie.
lim (1 - tanx)/(sinx - cosx) =
x-> pi/4
lim -sec^2x/(cosx + sinx) = -(√2)^2/(√2/2 + √2/2) = -2/(√2) = -√2
x-> pi/4