TRIANGULAR maximum problem (1 Viewer)

[MrBrightside]

sry dude, i keep coming across qs i can't do, because this ones asking about a triangle :S

does it use Pythagoras somewhere? I have a feeling it does.

View attachment 22443

thanks

 

[ohexploitable]

You need to find an expression for y in terms of x using Pythagoras.

 

[MrBrightside]

You need to find an expression for y in terms of x using Pythagoras.

yeah I did part a.

how do you get part b ? does A' = 1/2.2x^2(25-x)^-1/2

 

[Alkanes]

Differentiate it

 

[MrBrightside]

Differentiate it

thats what I did above ^

 

[ohexploitable]

does A' = 1/2.2x^2(25-x)^-1/2

There's your problem.

 

[YaMiTe]

A' = -x^2/[2(25-x^2)^1/2] + [(25-x^2)^1/2 ]/ 2 = 0
= -x^2+25-x^2 = 0
2x^2=25

x= root 12.5 (12.5)^1/2

Then sub x back into A.