Live practice

Choose a course and topic, attempt each question and open its complete worked solution when you are ready.

Reset
Question 1551
StructuredStandard4 marks
CBSE Class 11 Mathematics · Trigonometric Functions · Compound-angle identities

Prove that (cos x+cos y)²+(sin x−sin y)²=4cos²((x+y)/2).

Question 1552
StructuredStandard5 marks
CBSE Class 11 Mathematics · Limits and Derivatives · Rules of differentiation

Differentiate sin(x+a).

Question 1553
StructuredStandard5 marks
CBSE Class 11 Mathematics · Conic Sections · Hyperbolas

A hyperbola has foci (±5,0) and transverse-axis length 8. Find its equation.

Question 1554
StructuredStandard5 marks
CBSE Class 11 Mathematics · Straight Lines · Distance and intersections

Find both lines through (3,2) making 45° with x−2y=3.

Question 1555
StructuredStandard5 marks
CBSE Class 11 Mathematics · Sequences and Series · Special series and applications

Find the n-term sums of (i) 5+55+555+⋯(ii) 0.6+0.66+0.666+⋯ .

Question 1556
StructuredStandard4 marks
CBSE Class 11 Mathematics · Trigonometric Functions · Multiple and half angles

Complete every requested part of miscellaneous exercise, question 4: (cos x – cos y)2 + (sin x – sin y)2 = 4 sin2 2

Question 1557
StructuredStandard5 marks
CBSE Class 11 Chemistry · Equilibrium · Acid-base equilibria and pH

If \(0.561\,\mathrm{g}\) of KOH is dissolved in

(a)
water to give 200 mL of solution at 298 K. Determine the concentrations of potassium
(b)
hydrogen
(c)
hydroxyl ions. Determine its pH?
Question 1558
StructuredStandard3 marks
CBSE Class 11 Chemistry · Structure of Atom · Matter waves and uncertainty principle

An electron microscope uses electrons moving at 1.6 × 10⁶ \(\mathrm{m\,s}\)⁻¹. Calculate their de Broglie wavelength.

Question 1559
StructuredStandard5 marks
CBSE Class 11 Mathematics · Limits and Derivatives · Rules of differentiation

Differentiate cosec x cot x.

Question 1560
StructuredStandard5 marks
CBSE Class 11 Mathematics · Conic Sections · Hyperbolas

A hyperbola has foci (0,±13) and conjugate-axis length 24. Find its equation.