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Given that y = 8x + 2x^-1, find the 2 values for x for which dy/dx = 0

First differentiate y with respect to x, which gives you dy/dx = 8 - 2x^-2. This needs to equal zero so equate to zero. 8-2x^-2 = 0. You can then bring the 2x^-2 to the other side giving 2x^-2=8. Dividing bo...
RB
Answered by Rosemary B. • Maths tutor
4419 Views

Differentiate y = 4exp(6x) + cos(x) + 6x

dy/dx = 24e 6x - sin(x) + 6
BC
Answered by Benn C. • Maths tutor
4710 Views

Express 2 cos x – sin x in the form Rcos( x + a ), where R and a are constants, R > 0 and a is between 0 and 90 ° Give the exact value of R and give the value of to 2 decimal places.

2cosx - sinx = Rcos(x+a) = Rcos(x)cos(a)-Rsin(x)sin(a) Implying 2cos(x)=Rcos(x)cos(a) Rcosa = 2 Similarly: Rsin(a) = 1 Therefore tan(a) = 1/2 Meaning a=26.57 Degrees R 2 (sin 2 a+cos 2 a)=5 Implying, given s...
TO
Answered by Thomas O. • Maths tutor
33848 Views

Integrate ln(x).

When tackling an unobvious integral question, first run through all the possible methods. I will now list the methods of integration: Substitution: could use this method, but it wouldn’t be particularly help...
MC
Answered by Melanie C. • Maths tutor
4916 Views

Find the derivative with respect to x and the x-coordinate of the stationary point of: y=(4x^2+1)^5

y=(4x^2+1)^5 y=u^5 u=4x^2+1 y’=5u^4 (wrt u) u’=8x y’=40x(4x^2+1)^4 y’=40x(4x^2+1)^4=0 x=0 (x^2+1>0)
EB
Answered by Ellie B. • Maths tutor
4583 Views