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If g(x)={αxx,if x<05,if x0g(x) = \begin{cases} \frac{αx}{|x|}, & \text{if } x < 0 \\ 5, & \text{if } x ≥ 0 \end{cases} is continuous at x = 0, then the value of α is

Solution

Correct Option: 3

For g(x)g(x) to be continuous at x=0x = 0:

limx0g(x)=limx0+g(x)=g(0)\lim_{x \to 0^-} g(x) = \lim_{x \to 0^+} g(x) = g(0)


Since x=0x = 0 satisfies the condition x0x ≥ 0, we use the second part of the function:

g(0)=5g(0) = 5


When xx approaches 00 from the right (where x>0x > 0), the condition x0x ≥ 0 applies:

limx0+g(x)=limx0+5=5\lim_{x \to 0^+} g(x) = \lim_{x \to 0^+} 5 = 5


When x<0x < 0, we use g(x)=αxxg(x) = \frac{αx}{|x|}

For negative values of xx, we have x=x|x| = -x

Substituting:

g(x)=αxxg(x) = \frac{αx}{|x|}

g(x)=αxxg(x) = \frac{αx}{-x}

g(x)=αg(x) = -α

Therefore:

limx0g(x)=α\lim_{x \to 0^-} g(x) = -α


Setting all three values equal:

α=5-α = 5

α=5α = -5

Therefore, α=5α = -5

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