Let P be the point on the parabola y2=4x which is at the shortest distance from the center S of the circle x2+y2−4x−16y+64=0. Let Q be the point on the circle dividing the line segment SP internally. Then (1) SP=25 (2) SQ:QP=(5+1):2 (3) the x-intercept of the normal to the parabola at P is 6 (4) the slope of the tangent to the circle at Q is 21
Answers:A. SP=25 · C. the x-intercept of the normal to the parabola at P is 6 · D. the slope of the tangent to the circle at Q is 21
Let P be the point on the parabola y² = 4x which is at the shortest distance from the center S of the circle x² + y² - 4x - 16y + 64 = 0. Let Q be the point on the circle dividing the line segment SP internally. Then
y2=4x(parabola)
x2+y2−4x−16y+64=0(circle)
S=centre of the circle
P∈y2=4x nearest to S
Q∈circle,Q divides SP internally
To find: correct statement(s)
x2+y2−4x−16y+64=0⇒(x−2)2+(y−8)2=4⇒S(2,8),r=2y2=4x⇒a=1,vertex (0,0)1.shortest SP⇒SP is the normal at P2.SP through S⇒P3.check options (1)–(4)SP⊥tangent at P⇒SP is the normalnormal at param t:y=−tx+2t+t3(a=1)S(2,8):8=−2t+2t+t3⇒t3=8⇒t=2P=(t2,2t)=(4,4)SP=(4−2)2+(4−8)2=20=25✓SQ=r=2,QP=25−2QPSQ=25−22=5−11=45+1=25+1×t=2:y=−2x+12y=0⇒x=6✓mSQ=4−24−8=−2mtangent=−−21=21✓True: (1), (3), (4);(2) is falseCorrect options: (1), (3), (4)