Chapter 4, Problem 45RE

If a shark is spotted near to Brighton beach, a lifeguard will activate a siren to wai Siren The sound intensity, I, of the siren varies inversely with the square of the distance, d, from the siren, where d>0. It is known that at a distance of 1.5 metres from the siren, the sound intensity is 4 watts per square metre (Wm). (a) 9. Show that / = (b) Sketch the curve of / on the axes below showing clearly the point (1.5,4). 20 -5-

Determine an equation of the line tangent to the curve y = /5x-4 at the point with x- coordinate 4. Paragraph BIU A II lilh

Tangent lines are drawn to the curve y = -x2 − 2 from the point (0, 2). Find the points at which the tangent lines touch the curve. Also illustrate with a diagram.