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Dominik hires a satellite phone. His total hire charge is £860. For how many weeks did he hire the phone? (Total hire charge = No. of week X 90 +50)

Rearrange the formula so that it is equal to what the question is asking for (no. of weeks) What you have to do to one side you must do to the other! Total hire charge - 50 = No. of weeks X 90 (Total hire ch...
GK
Answered by Grace K. • Maths tutor
4800 Views

What is the definite integral of 2x^2 + 4x + 1 with a lower limit of 3 and a higher limit of 6?

When integrating we add one to the power of x and divide the number in front of the x by the new power for each part of the function. So 2x^2 becomes 2/3 x^3, 4x becomes 4/2 x^2, 1 becomes 1/1 x^1. Then we n...
EL
Answered by Ed L. • Maths tutor
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A curve C is defined by the equation sin3y + 3y*e^(-2x) + 2x^2 = 5, find dy/dx

d(sin3y)/dx= 3cos3y*(dy/dx)d(3y e^(-2x))/dx = -6y e^(-2x) + 3(dy/dx) e^(-2x)d(2x^2)/dx = 4xd(5)/dx = 0so3cos3y (dy/dx) - 6y*e^(-2x) + 3(dy/dx) e^(-2x) + 4x = 0rearrange the equationdy/dx = (6y e^(-2x)-4x)/(3...
ZZ
Answered by Zhaohui Z. • Maths tutor
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if a^x= b^y = (ab)^(xy) prove that x+y =1

ln(a^x) = ln(b^y) = ln((ab)^(xy)) xln(a) = xyln(ab) ln(a) = yln(ab) = y(ln(a) + ln(b)) y = ln(a)/(ln(a)+ln(b)) with same analysis for ln(b^y): ln(b) = x(ln(a) + ln(b))x = ln(b)/(ln(a)+ln(b)) x + y = (ln(a) +...
SC
Answered by Scott C. • Maths tutor
6426 Views

f(x)=2x+c, g(x) = cx+5, fg(x)= 6x+d, work out the value of d

Let’s call (f(x)=2x+c) equation 1, (g(x) = cx+5) equation 2 and (fg(x)= 6x+d) equation 3. Start by finding fg(x) in terms of c by substituting (equation 2) into (equation 1) to get (fg(x)= 2(cx +5) + c). You...
AM
Answered by Anna M. • Maths tutor
4378 Views