alleryThe roots of the equation $x^2 + 1 = 0$ are:
A$0$ only
B$\pm 1$
C$\pm 2i$
D$\pm i$
Answer & Solution
Correct answer: D. $\pm i$
We have x² = −1 ⟹ x.
That is x² = ±√(−1).
So x² = ±i.
Keep practising Unit 3A: Chain Rule and Composite Functions
Browse all Unit 3A: Chain Rule and Composite Functions questions for AP Calculus AB, or explore more Mathematics topics.
Related questions
In which quadrant is sin θ positive and cos θ negative?If tan θ + cot θ = 2, find sin 2θ:General solution of sin θ = sin α:In triangle with sides 7, 8, 9, find cos of the angle opposite to side 9 (use cosine rule)If sin θ = 12/13 (acute), find tan(θ/2):General solution of cos θ = 0:If sin θ + cos θ = 1, then sin θ × cos θ equals:In triangle ABC with sides a, b, c opposite to angles A, B, C: sine rule states: