# Differential Calculus

The base of an isosceles triangle is 10 feet long and the base angles are decreasing at a rate of 2° per second. Find the rate of change of the area when the base angles are 45°.

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1. we have the height h is

h = 5tanθ

a = 5h = 25tanθ
da/dt = 25sec^2θ dθ/dt

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2. Thank you Sir ☺

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3. But where did the a=5h come from?

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4. did you actually draw an isosceles triangle with a base of 10?

A = 1/2 bh

Let's not forget the basics now that we're in calculus!

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5. Oh yes. Sorry sir. i just got confused. Thank you :)

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