SOLUTION: 2= sqr22-8x^2

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Question 102979This question is from textbook Longman Mathematics for IGCSE Maths
: 2= sqr22-8x^2 This question is from textbook Longman Mathematics for IGCSE Maths

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
2=sqrt%2822%29-8x%5E2 I assume this is the problem.
8x^2+2=sqrt(22)
64x^4+32x^2+4=22 Square both sides.
64X^4+32x^2-18=0
32x^4+16x^2-9=0 divide each side by 2.
32x64+16x^2 =9
x^4+.5x^2+.0625=9/32+.0625 Complete the square on the left by dividing each side by 32 an adding .0625 to each side.
(x^2+.25)^2=11/32
x^2+.25=sqrt(11/32)
x^2=-.25+-sqrt(11/16*2)
x^2=(-1+-sqrt(11/2))/4
x=+-sqrt(-1-sqrt(11/2))/2 gives non real results
x=+-sqrt(-1+sqrt(11/2))/2=+-.579915
graph%28500%2C500%2C-5%2C5%2C-5%2C5%2Csqrt%2822%29-8x%5E2-2%29
Ed