Which of the following statements is false ? (A) 45°= 45° (B) 90°= 45° (C) 30°= 30° (D) 45°= 45°

MathsCBSE Class 10 · Basic · Board exam 2025, set 430/1/1 · 1 mark · MCQ

CBSE Class 10 Mathematics Basic 2025: question 10

Set in the CBSE Class 10 board exam of 2025, paper 430/1/1, section A, question 10, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q10 · 1 mark · MCQIntroduction to Trigonometry

Which of the following statements is false ?

(A) $tan 4 5^{\circ} = cot 4 5^{\circ}$
(B) $sin 9 0^{\circ} = tan 4 5^{\circ}$
(C) $sin 3 0^{\circ} = cos 3 0^{\circ}$
(D) $sin 4 5^{\circ} = cos 4 5^{\circ}$

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 430/1/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Write down the value of each ratio from the standard table.

Hint 2

Compare $sin 3 0^{\circ}$ and $cos 3 0^{\circ}$ .

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

$tan 4 5^{\circ} = cot 4 5^{\circ} = 1$ , $sin 9 0^{\circ} = tan 4 5^{\circ} = 1$ , and $sin 4 5^{\circ} = cos 4 5^{\circ} = \frac{1}{2}$ , so (A), (B) and (D) are true.
$sin 3 0^{\circ} = \frac{1}{2}$ but $cos 3 0^{\circ} = \frac{3}{2}$ , so statement (C) is false. The answer is option (C).
1 mark

Answer: Option (C)

Where the marks are

Identifies sin 30° ≠ cos 30° (1 mark)

Revise the chapter

Chapter: Introduction to Trigonometry (notes, formulas, where marks are lost and every past question)
Topic: Relationships Between Trigonometric Ratios

Practise this chapterBoard-style questions from Introduction to Trigonometry, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 430/1/1 (Basic): every question, by section.

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CBSE Class 10 Mathematics Basic 2025: question 10

Hints

Step-by-step solution

Revise the chapter

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