Upon differentiating, we can write the derivative in terms of e.
Multiply through by to shed the fractions:
Now, you can let and get:
Solving this we find the real solutions are
Since we see the solutions are:
Q show curve y=cosh2x -10coshx+13 has three stat points and find y co-ord of stat points,,,
i get (0,4) (-ln(6.25+(5.25)^0.5,-6.19) (ln(6.25+(5.25)^0.5,6.19)
im using calc fx-9750 PLUS and the *** thing when i trace the stat points gives (0,4) and (-1.6,-0.5) and (1.6,0.5) so i concluded i must be wrong,,,,,,,does n e one know where ive gone wrong? previously useddouble angle cosh2x=2cosh^2x-1 then for y co-ords both expansion using cosh 2x=0.5(e^x etc and bunging in calc gave me 6.19)
can some1 pls help!
thnx where did i go wrong with d/dx(cosh2x-10coshx+13)
= 2sihx -10sinhx
=0 using sinh2x=2sinhxcoshx
4sinhxcoshx-10sinhx=0
2sinhx(2coshx-5)=0
sinhx=0 x=0 2coshx=5
x=arcosh2.5
x=+/- ln(6.25+(5.25^0.5) ??? ur method confused me when u^4 -5u^3 +5u -1=o
i did u(U^3-5u^2+5)=1
which gives u=1 not u=-1 then i think i do u^2(u-5)=-4