MP Board · Class 10 · Mathematics · Introduction to TrigonometryIf $\sin A = \frac{3}{4}$, then what is the value of $\cos A$?
Using the trigonometric identity $\sin^2 A + \cos^2 A = 1$:
$$\cos^2 A = 1 - \sin^2 A$$ $$\cos^2 A = 1 - \left(\frac{3}{4}\right)^2 = 1 - \frac{9}{16} = \frac{16 - 9}{16} = \frac{7}{16}$$ \nTaking the square root on both sides: $$\cos A = \sqrt{\frac{7}{16}} = \frac{\sqrt{7}}{4}$$ \nHence, the correct option is (B).
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Introduction to Trigonometry.
Correct choice. Refer to the step-by-step verified solution guidelines above for details.
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Introduction to Trigonometry.
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Introduction to Trigonometry.