Error detection in standard values

1. Locate the angle. 2. Recall the correct value from the standard table. 3. Compare with the given entry. 4. Correct the swapped or mismatched value.

A standard value chart or a 30-60-90 triangle sketch helps detect swapped entries quickly.

A common wrong answer is to trust the written table because it looks neat. In trig, neat does not mean correct.

Error detection in standard values means finding and correcting wrong entries in the standard trigonometric value table.

Error detection in standard values means finding and correcting wrong entries in the standard trigonometric value table. Standard values must follow the correct table: sin 30 = 1/2, sin 60 = root 3/2, cos 30 = root 3/2, cos 60 = 1/2, tan 45 = 1, and tan 90 is not defined. If a table shows cos 60 degrees as root 3 over 2, that is wrong because cos 60 degrees should be 1/2.

This skill is important because CBSE often tests whether students truly know the values or only memorized them partly. The most common errors are swapping 30 degrees and 60 degrees, confusing sine with cosine, and forgetting that tan 90 degrees is not defined. Careful comparison is the best way to catch mistakes. Standard values must follow the correct table: sin 30 = 1/2, sin 60 = root 3/2, cos 30 = root 3/2, cos 60 = 1/2, tan 45 = 1, and tan 90 is not defined. If a learner writes cos 30 degrees = 1/2, the correction is root 3 over 2. This shows the common swap between 30 degrees and 60 degrees. CBSE may present a table with one wrong value and ask students to identify the error, or may ask for the correct value directly. A common wrong answer is to trust the written table because it looks neat. In trig, neat does not mean correct.