In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No error'.
I am vexed at him (1)/ for what all he has (2)/ done for him till date. (3)/ No Error (4)

What is the value of [sec θ/(sec θ – 1)] + [sec θ/(sec θ + 1)]

A boat is sailing towards a lighthouse of height 20√3 m at a certain speed. The angle of elevation of the top of the lighthouse changes from 30° to 60° in 10 seconds. What is the time taken (in seconds) by the boat to reach the lighthouse from its initial position?

In a triangle ABC, AD is angle bisector of ∠A and AB : AC = 3 : 4. If the area of triangle ABC is 350 cm2, then what is the area (in cm2) of triangle ABD?

ABC is an equilateral triangle and P is the orthocenter of the triangle, then what is the value (in degrees) of ∠BPC?

The point of intersection of all the angle bisector of a triangle is ______ of the triangle.

The inradius of a equilateral triangle is 10 cm. What is the circum-radius (in cm) of the same triangle?

If 27x + 27[x–(1/3)] = 972, then what is the value of x?