Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Continuity and Differentiability

Question:

Find the value of k making the following function continuous at x = 5

$f(x)= \begin{cases}2 k x-1, & x ≥ 5 \\ 2 x+3, & x<5\end{cases}$

Options:

$\frac{5}{7}$

0

$\frac{5}{6}$

$\frac{7}{5}$

Correct Answer:

$\frac{7}{5}$

Explanation:

The correct answer is Option (4) → $\frac{7}{5}$

$f(5)=10k-1$

$\underset{x→5^-}{\lim}(2x+3)=13$

so for continuity at $x=5$

$12=10k-1⇒k=\frac{7}{5}$