Trying to find dy/dx of a trig function # 2

  • Thread starter Thread starter jtt
  • Start date Start date
  • Tags Tags
    Function Trig
jtt
Messages
16
Reaction score
0

Homework Statement


find dy/dx


Homework Equations


x+tanxy=0


The Attempt at a Solution


d/dy(x+tanxy)

x+sec^2(xy)((1)(dy/dx))+(1)(tanxy)=0
dy/dx(sec^2(xy)+x+tanxy=0
-x-tanxy -x-tanxy
dy/dx(sec^2(xy)/(sec^2(xy)=(-x-tanxy)/(sec^2(xy))

dy/dx=(-x-tanxy)/(sec^2xy)
 
Physics news on Phys.org
jtt said:

Homework Statement


find dy/dx


Homework Equations


x+tanxy=0

You can begin by stating the problem unambiguously. Are you trying to differentiate

x + tan(xy) = 0 or x + ytan(x)=0. The point is that as it is written we can't tell whether the y is inside or outside that tangent function. Parentheses are necessary!

The Attempt at a Solution


d/dy(x+tanxy)

Why are you writing d/dy when you are differentiating with respect to x?
 
trying to differentiate x+tan(xy)

i got dy/dx when i took the derivative of y in tan(xy)
 
jtt said:

Homework Statement


find dy/dx


Homework Equations


x+tanxy=0


The Attempt at a Solution


d/dy(x+tanxy)

You mean d/dx(x + tan(xy))

x+sec^2(xy)((1)(dy/dx))+(1)(tanxy)=0
Is the derivative of x equal to x??

And what I highlighted in red should be the derivative of the (xy) which is the argument of the tangent function, or the "inside". There should be no tan(xy) in that.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top