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Given that y = 16x + x^-1, find the two values of x for which dy/dx = 0

Expected layout of answer in an exam: y = 16x + x -1 dy/dx = 16 - x -2 dy/dx = 0 implies that 16 - x -2 = 0this implies that 16 = x -2 16 = 1/x 2 16x 2 = 1x 2 = 1/16therefore x = +/- 1/4x = 1/4, x = -1/4 whe...
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Answered by Sawdah H. • Maths tutor
4521 Views

multiply out (2x-4)(x-2) and simplify.

The method I would use here is FOIL (first outer inner last). A common mistake is not multiplying out all terms, using FOIL will ensure you do this.The working I would expect to see:2x^2-4x-4x+8 (order shows...
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Answered by Ben W. • Maths tutor
4586 Views

Solve the simultaneous equations: 3x+2y=11, 2x-5y=1.

Step 1) Label Equations 1) 3x+2y=11 2) 2x-5y=1 Step 2) Multiply so that one variable has same coefficient in both equations. 1)x5 15x+10y=55 2)x2 4x-10y=2 Step 3) Add/Subtract equations to remove one variabl...
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Answered by Harry B. • Maths tutor
5930 Views

Factorise x^2 + 4x +3

First take the 4x - the two numbers that will be +/- to the x in the brackets will need to add to form this number, so the possibilities are 1 and 3 or 2 and 2.Now take the 3 - the two numbers that will be +...
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Answered by James S. • Maths tutor
9313 Views

How to Solve Two Simultaneous Equations

I will use the whiteboard in order to explain the answer to my question. The format will follow:Understanding what it means to 'solve' one equationUnderstanding what it means to 'solve' two equationsVariable...
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Answered by Matthew I. • Maths tutor
3407 Views