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Find the inverse of the matrix C=(1,2;4,9)

Give the general formula for determinant and inverse of 2x2 matrix. Calculate determinant=1 9-2 8=1 using formula inverse=1/determinant*(8,-2;-4,1)
NA
Answered by Nefeli A. • Maths tutor
3445 Views

ABC, DEF and PQRS are parallel lines. BEQ is a straight line. Angle ABE = 60° Angle QER = 80° Work out the size of the angle marked x. Give reasons for each stage of your working.

Angles ABE and EQR are alternate interior angles. This means they are the same thus angle EQR = 60˚. We know that the sum of the interior angles of a triangle is equal to 180˚ and we know that angle QER = 80...
JP
Answered by Juliana P. • Maths tutor
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Solve this set of simultaneous equations: 5x+3=3y 9x+9=6y

Firstly, you need to understand that the two equations are interlinked, therefore the x and the y variables are the same values in both equations. To make things easier, we can number both equations. What we...
RJ
Answered by Ryan J. • Maths tutor
3436 Views

Prove the identity: (sinx - tanx)(cosx - cotx) = (sinx - 1)(cosx - 1)

(sinx - tanx)(cosx - cotx)= (sinx - sinx/cosx)(cosx - cosx/sinx)= sinxcosx - (sinx + cosx) + 1= (sinx - 1)(cosx - 1)
CP
Answered by Charlie P. • Maths tutor
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For what values of k does the line y=kx-1 have two distinct points of intersection with the circle (x-2)^2+(y-3)^2=2?

sub y=kx-1 into circle equation, get (k^2+1)x^2-(8k+4)x+18=0for 2 distinct solutions need b^2-4ac>0, ie -8k^2+64k-56>0iff k^2-8k+7<0complete the square: intersections of equation in k satisfy(k-4)^2...
CB
Answered by Christopher B. • Maths tutor
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