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Why is sin(t)^2 + cos(t)^2 = 1 true for all t?

To answer this we need to consider a circle of radius r centred at the origin, drawn in the x,y plane. We'll draw a right-angled triangle such that the hypotenuse is the radius, and say that the point whe...

Answered by Matt V. • Maths tutor

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(a) Use integration by parts to find ∫ x sin(3x) dx

The question asks for integration by parts. Therefore we need to differentiate one variable and integrate the other. First we need to decide which variable is going to be which. Algebra should always be d...

Answered by George A. • Maths tutor

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What's the gradient of the curve y=x^3+2x^2 at the point where x=2?

Gradient is change in y divided change in x.As the change shrinks to effectively nothing (as we want to gradient at a point, not between points), we use dy/dx (the derivative of y with respect to x), to w...

Answered by Zachary I. • Maths tutor

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Solve the simultaneous equations: y = x + 6, x^2 + 2y = 9

y = x + 3x² + 2y = 9We want to make the squared equation have either only x's or only y's, so we substitute y = x + 3 into the equation:x² + 2(x + 3) = 9We need to take out the brack...

Answered by Hayley H. • Maths tutor

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Prove by induction that, for n ∈ Z⁺ , [3 , -2 ; 2 , -1]ⁿ = [2n+1 , -2n ; 2n , 1-2n]

STEP 1: Prove that the theorem holds for n = 1. Substitute n = 1 into the equation and show that the LHS = RHS.
STEP 2: Assume that the relation is true when n = k.
STEP 3: Prove that the relat...

Answered by Flavia T. • Maths tutor

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