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RE: Test Your Math Skills and Win SBD # 2

in #contest7 years ago (edited)

2 & 4 are true.

  • No. 1 is false when x = -1.
    (-1)^2 =1 & (=1)^4=1, therefore x^2=x^4 when x= -1.

  • No. 2 is true at all times. A negative number when raised to an odd power will always give you a negative result. A negative number raised by an even power will have a positive result. Therefore, x^3 < x^2 is true.

  • No. 3 is false since the result of x + 1/x will always be a positive fraction except when x=-1 because it will give you an undefined result. Therefore x + 1/x < 0 is not true.
    Example:
    -2 +1/-2
    = -1/-2
    =1/2
    1/2 > 0.

  • No. 4 is true. All positive real numbers has two square roots, one positive square root and one negative square root. The positive square root is sometimes referred to as the principal square root.

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Negative x to 3 power is negative. Negative x to 2 power is positive. Therefore No.2 x3 < x2 is true.

For the third one, the restriction is at x = 0.

@dkmathstats, yes but the questions says If X is a negative integer. 0 is a special number.

Zero is neither negative nor positive.

There may be confusion in the third question.

I'm viewing the third question as the first one from the above. Given x as a negative, the sum is negative.

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