Q.
Let O be the origin, OP and OQ be two perpendicular chords of equal length of the circle x2+y2−4x+8y=0. Let m1 and m2 be the slopes of chords OP and OQ.
Evaluate ∣∣m2m1∣∣, where m1>m2.
x2+y2−4x+8y=0 ⇔(x−2)2+(y+4)2=20
Centre C=(2,−4)
Slope of OC=2−0−4−0=−2
Let OP have slope m. Then tan45∘=∣∣1−2mm+2∣∣ ⇔m+2=±(1−2m) ⇔3m=−1 or m=3 ⇒m1=3,m2=−31 ⇔∣∣m2m1∣∣=∣∣(−31)3∣∣=9