An Isosceles triangle has two equal sides of length 10cm. Let x be the angle between the two equal sides.(adsbygoogle = window.adsbygoogle || []).push({});

a. Express the area A of the triangle as a function of x in radians.

b. Suppose that x is increasing at the rate of 10 degrees per minute. How fast is A changing at the instant x = pi/3? At what value of x will the triangle have a maximum area?

I've set the triangle and drew a line to cut it in half. the angle is now x/2, and the base is b/2. The hypoteneuse of each triangle is 10.

cos x/2 = adj/hyp = h/10

sin x/2 = opp/hyp = b/2/10 = b/20

A = 100sinx/2 cosx/2

= 100 sinx/2

would that be the equation for part a?

any help for part b would be greatly appreciated.

thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Rate of change in an Isosceles triangle

**Physics Forums | Science Articles, Homework Help, Discussion**