Here are the derivatives for the remaining functions:
6. sin(x+y)=y2cosx
Step 1: Differentiate both sides with respect to x. Remember to use the chain rule for terms involving y and the product rule for y2cosx.
dxd(sin(x+y))=dxd(y2cosx)
cos(x+y)⋅dxd(x+y)=dxd(y2)cosx+y2dxd(cosx)
cos(x+y)(1+dxdy)=2ydxdycosx+y2(−sinx)
cos(x+y)+cos(x+y)dxdy=2ycosxdxdy−y2sinx
Step 2: Rearrange the equation to group terms with dxdy on one side.
cos(x+y)dxdy−2ycosxdxdy=−y2sinx−cos(x+y)
Step 3: Factor out dxdy.
dxdy(cos(x+y)−2ycosx)=−y2sinx−cos(x+y)
Step 4: Solve for dxdy.
dxdy=cos(x+y)−2ycosx−y2sinx−cos(x+y)
\frac{dy}{dx} = \frac{y^2 \sin x + \cos(x + y){2y \cos x - \cos(x + y)}}
7. f(x)=arctan(1−x22x)
Step 1: Recall the derivative of arctan(u) is 1+u21dxdu.
Let u=1−x22x.
Step 2: Find dxdu using the quotient rule.
Let p=2x and q=1−x2. Then p′=2 and q′=−2x.
dxdu=q2p′q−pq′=(1−x2)2(2)(1−x2)−(2x)(−2x)
dxdu=(1−x2)22−2x2+4x2=(1−x2)22+2x2=(1−x2)22(1+x2)
Step 3: Substitute u and dxdu into the derivative formula for arctan(u).
f′(x)=1+(1−x22x)21⋅(1−x2)22(1+x2)
f′(x)=1+(1−x2)24x21⋅(1−x2)22(1+x2)
f′(x)=(1−x2)2(1−x2)2+4x21⋅(1−x2)22(1+x2)
f′(x)=(1−x2)2+4x2(1−x2)2⋅(1−x2)22(1+x2)
f′(x)=(1−x2)2+4x22(1+x2)
Step 4: Expand the denominator.
(1−x2)2+4x2=1−2x2+x4+4x2=1+2x2+x4=(1+x2)2
Step 5: Substitute the simplified denominator back into f′(x).
f′(x)=(1+x2)22(1+x2)
f'(x) = \frac{2{1 + x^2}}
Note: This result is consistent with the identity 2arctan(x)=arctan(1−x22x) for ∣x∣<1, as dxd(2arctan(x))=1+x22.
8. y=ln(sinhx+coshx)
Step 1: Use the identity sinhx+coshx=ex.
y=ln(ex)
Step 2: Simplify the function using logarithm properties.
y=x
Step 3: Differentiate y with respect to x.
dxdy=dxd(x)
dxdy=1
9. y=eex
Step 1: Apply the chain rule. The derivative of eu is eudxdu.
Let u=ex.
dxdy=eu⋅dxdu
Step 2: Find dxdu.
dxdu=dxd(ex)=ex
Step 3: Substitute u and dxdu back into the expression for dxdy.
dxdy=eex⋅ex
dxdy=exeex
10. y=x2+1x (Find dx2d2y)
Step 1: Find the first derivative dxdy using the quotient rule.
Let u=x and v=x2+1. Then u′=1 and v′=2x.
dxdy=v2u′v−uv′=(x2+1)2(1)(x2+1)−(x)(2x)
dxdy=(x2+1)2x2+1−2x2
dxdy=(x2+1)21−x2
Step 2: Find the second derivative dx2d2y by differentiating dxdy using the quotient rule again.
Let p=1−x2 and q=(x2+1)2.
Then p′=−2x.
For q′, use the chain rule: q′=2(x2+1)⋅(2x)=4x(x2+1).
dx2d2y=q2p′q−pq′
dx2d2y=((x2+1)2)2(−2x)(x2+1)2−(1−x2)(4x(x2+1))
dx2d2y=(x2+1)4(−2x)(x2+1)2−4x(1−x2)(x2+1)
Step 3: Factor out common terms from the numerator, specifically −2x(x2+1).
dx2d2y=(x2+1)4−2x(x2+1)[(x2+1)+2(1−x2)]
dx2d2y=(x2+1)3−2x[(x2+1)+2−2x2]
dx2d2y=(x2+1)3−2x[3−x2]
\frac{d^2y}{dx^2} = \frac{2x(x^2 - 3){(x^2 + 1)^3}}
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