In this question, the sin (2x) is a power of the base, cos x.
`cos x ^(sin 2x)`
To find the derivative, the natural logarithm function is used.
Let y equal cosx ^ (sin 2x).
`y=cosx^((sin2x))`
Take the natural logarithm of both sides.
`ln [y] = ln[cosx^((sin2x))]`
Use the logarithm property that ln[x^b] = b*ln[x].
`ln[y]=(sin2x)*ln[cosx]`
Take the derivative of both sides using implicit differentiation and the product rule.
`1/y * dy/dx=(sin2x)*1/cosx*(-sinx)+ln[cosx]*cos(2x)*2`
Multiply both sides by y.
`dy/dx=y[(sin2x)*1/cosx*(-sinx)+ln[cosx]*cos(2x)*2]`
Replace y with the cosx^(sin2x).
`dy/dx=cosx^(sin2x)[(sin2x)*1/cosx*(-sinx)+ln[cosx]*cos(2x)*2]`
The derivative can be simplified in many different forms. My suggestion is have sin/cos become tangent.
One simplified form of the derivative is:
`d/dx(cosx^(sin2x))=cosx^(sin2x)[-(sin2x)(tanx)+2(cos2x)ln[cosx]]`
we have to find d(cosx * sin2x)/dx.
This can be simply done by using the principle of deriavation of multiplications.
d(cosx * sin2x)/dx = cosx * d(sin2x)/dx + sin2x * d(cosx)/dx
= cosx*2*cos2x+ sin2x*(-sinx)
= 2*cosx*cos2x - sinx*sin2x
=2*cosx*cos2x - sinx*2*sinx*cosx (sin2x = 2*sinx*cosx)
= 2*cosx* [cos2x-(sinx)^2]
= 2*cosx*[(cosx)^2 - (sinx)^2-(sinx)^2]
(cos2x = (cosx)^2 - (sinx)^2)
d(cosx * sin2x)/dx= 2*cosx[(cosx)^2 - 2*(sinx)^2]
See eNotes Ad-Free
Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.
Already a member? Log in here.