Home
Class 12
MATHS
Assertion (A) |sinx| is continuous at x=...

Assertion (A) `|sinx|` is continuous at x=0 .
Reason (R ) : |sinx| is differentiable at x=0.

A

Both A and R are true and R is the correct explanation of A

B

Both A and R are true but R is NOT the correct explanation of A

C

A is true but R is false

D

A is false and R is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the assertion and the reason provided. **Assertion (A)**: \(|\sin x|\) is continuous at \(x = 0\). **Reason (R)**: \(|\sin x|\) is differentiable at \(x = 0\). ### Step-by-Step Solution: 1. **Check Continuity of \(|\sin x|\) at \(x = 0\)**: - A function \(f(x)\) is continuous at a point \(c\) if: \[ \lim_{x \to c} f(x) = f(c) \] - Here, we need to check if \(\lim_{x \to 0} |\sin x| = |\sin(0)|\). - We know that \(\sin(0) = 0\), so \(|\sin(0)| = 0\). - Now, calculate the limit: \[ \lim_{x \to 0} |\sin x| = |\sin(0)| = 0 \] - Since both sides are equal, \(|\sin x|\) is continuous at \(x = 0\). 2. **Check Differentiability of \(|\sin x|\) at \(x = 0\)**: - A function is differentiable at a point if the derivative exists at that point. - We need to find the left-hand and right-hand derivatives at \(x = 0\). - For \(x \geq 0\), \(|\sin x| = \sin x\). \[ f'(0^+) = \lim_{h \to 0^+} \frac{f(h) - f(0)}{h} = \lim_{h \to 0^+} \frac{\sin h - 0}{h} = \lim_{h \to 0^+} \frac{\sin h}{h} = 1 \] - For \(x < 0\), \(|\sin x| = -\sin x\). \[ f'(0^-) = \lim_{h \to 0^-} \frac{f(h) - f(0)}{h} = \lim_{h \to 0^-} \frac{-\sin h - 0}{h} = \lim_{h \to 0^-} \frac{-\sin h}{h} = -1 \] - Since the left-hand derivative \(f'(0^-)\) and the right-hand derivative \(f'(0^+)\) are not equal: \[ f'(0^+) = 1 \quad \text{and} \quad f'(0^-) = -1 \] - Thus, \(|\sin x|\) is not differentiable at \(x = 0\). 3. **Conclusion**: - The assertion (A) is true: \(|\sin x|\) is continuous at \(x = 0\). - The reason (R) is false: \(|\sin x|\) is not differentiable at \(x = 0\). ### Final Answer: - Assertion (A) is true, and Reason (R) is false.
Promotional Banner

Similar Questions

Explore conceptually related problems

Assertion (A) : |sinx| is continuous for all x inR . Reason (R ) : sinxand|x| are continuous in R.

Assertion (A) : f(x) = xsin ((1)/(x)) is differentiable at x=0 Reason (R): F(x)is continuous at x=0

Assertion (A) :f(x) =[x] is not differentiable at x=2. Reason (R ) f(x)=[x] is not continuous at x=2.

If f(x) = (log_(e)(1+x^(2)tanx))/(sinx^(3)), x != 0 is continuous at x = 0 then f(0) must be defined as

If the function f(x)={{:(sinx,xne0),(k,x=0):} is continuous at x = 0 than find the value of k?

Let f(x)={[x]x in I x-1x in I (where [.] denotes the greatest integer function) and g(x)={sinx+cosx ,x<0 1,xgeq0 . Then for f(g(x))a tx=0 (lim)_(xvec0)f(g(x)) exists but not continuous Continuous but not differentiable at x=0 Differentiable at x=0 (lim)_(xvec0)f(g(x)) does not exist f(x) is continuous but not differentiable