Chapter 8 · Question 6

Evaluate sin230+cos230\sin^2 30^\circ+\cos^2 30^\circ.

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Q6

Evaluate sin230+cos230\sin^2 30^\circ+\cos^2 30^\circ.

Answer Revealed
Direct Answer:
By the identity sin2A+cos2A=1\sin^2A+\cos^2A=1, the value is 11. Directly, (12)2+(32)2=14+34=1(\frac12)^2+(\frac{\sqrt3}{2})^2=\frac14+\frac34=1.

Simple Explanation

The identity makes it immediate: answer is 11.

Exam-Ready Structure

Using standard values, sin30=12\sin30^\circ=\frac12 and cos30=32\cos30^\circ=\frac{\sqrt3}{2}. Therefore sin230+cos230=14+34=1\sin^2 30^\circ+\cos^2 30^\circ=\frac14+\frac34=1.

Key Points

  • By the identity sin2A+cos2A=1\sin^2A+\cos^2A=1, the value is 11.
  • Use the NCERT formula or theorem carefully.
  • Write units and final conclusion where applicable.