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Given that d/dx(cosx)=-sinx show that d/dx(secx)=secx(tanx)

let y=sec(x) = 1/(cos(X)) = cos(x) -1 Thus dy/dx = -1(cos(x)) -2 (-sinx) = sin(x)/(cos(x)) 2 = 1/cos(x) x sin(x)/cos(x) =sec(x)tan(x)
OD
Answered by Owain D. • Maths tutor
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x = 0.045 (45 recurring). Prove algebraically that x can be written as 1/22

x=0.045 (45 recurring) 10x = 0.45 (45 recurring) 100x = 4.54 (54 recurring) 1000x = 45.45 (45 recurring) To get rid of the decimals: 1000x-10x = 45.45 - 0.45 990x = 45 x = 45/990 x = 9/198 (simplify by divid...
JT
Answered by John T. • Maths tutor
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How do I work out the area of a right angled triangle?

If we think about a right angled triangle, it is the same as one half of a square or rectangle. This is because if we join two right angled triangles at their diagonal sides, we make a square or rectangle. N...
CC
Answered by Ciaran C. • Maths tutor
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In a sports competition with 760 atheletes, the following pieces of information are true: 70% of the atheletes are runners, 40% of the men are not runners and 400 women are runners. How many women were there in total?

Firstly, we must identify the two things that we need to work out our answer. They are: How many male runners there are, and how many male non-runners there are, as once we have these, the remaining value wi...
CC
Answered by Ciaran C. • Maths tutor
4207 Views

Solve algebraically: 6a + b = 16 5a - 2b = 19

We have two algebraic equations and we are trying to find what a and b can equal to fit for both situations. 1. 6a + b = 16 2. 5a - 2b = 19 The easiest method is substitution because we can sub in an equatio...
SW
Answered by Sophie W. • Maths tutor
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