We know that higher math has always been a trouble for students. So many students find it difficult to inculcate the concepts of Trigonometry in Math. Read, tips to excel in Mathematics in board exams. However let’s bring this fact to your notice that trigonometry is a very scoring topic and once you get well acquainted it becomes understandable and easy to solve.
In trigonometry, questions are about measuring sides or angles of triangles. These range from that on arcs of same length in two circles; area cattle can cover given the length of a rope when it is tied to a point; angle between hour hand and minute hand, measure of the angles of a triangle being in AP. Trigonometric formulae on sine, cosine and tangent values using the squares of the mentioned trigonometric values do not find a place in SSC exams. This does not hold true even in case of CAT or XAT. The maximum number of questions in SSC and CAT or XAT exams from trigonometry in math could be three.
Kinds of questions from Trigonometry in Math:
- AP and triangles or quadrilaterals
Angles in triangles or quadrilaterals can be in Arithmetic Progression. These questions are easy to solve without using a Trigonometric concept. The only thing that is of importance here is that of degrees and radians. π radians = 180 degrees.
Example: The angles of a triangle are in AP. The number of grades, in the least, is to the number of radians in the greatest as 40:π. Find the angles in degrees.
Circum-radius and in-radius of a circle
Formulae for circum-radius and in-radius of a circle can be used.
Circum-radius
R = abc / 4*Area
R = a/2SinA = b/2Sin B = c/2 Sin C
In-radius of a circle (r)
r = Area / s
- Example: If in any triangle a = 13 cm, b = 14 cm, and c = 15 cm, find the in-radius of the circle.
- A horse trots uniformly along a circular track of 27 m. The angle subtended at the centre of the track by the arc passed over by the horse in 3 seconds is 70 degrees. What distance will the horse pass over in ½ minute?
- Heights & Distances
The angle between the object being looked at and the angle it makes with the eye of the person looking at the object considering a straight line parallel to the surface is the angle of elevation. These questions can be a part of SSC exams as well. In case of CAT & XAT, the questions can be that of a higher level of difficulty.
Example: A man on the top of a rock rising on a sea-shore observes a boat coming towards it. If it takes 10 minutes for the angle of depression to change from 30 degrees to 60 degrees, how soon the boat reached the shore?
- Area of a sector
Area of a sector is the area bound by an arc and two radii. The question can also be such that the ends of the radii are joined and we need to find the area on either side of the line.
Example:
- The area of a sector of a circle with radius r and central angle x is (1/2)xr2.
- The area of a sector of a circle of radius r and an arc of lengths is (1/2)rs.
- An arc AB of a circle subtends an angle x radians at the centre O of the circle. Given that the area of the sector AOB is equal to the square of the length of the arc AB, find the value of x.
Strategize
- The questions asked in exams from these concepts are not that complex. The ones based on formulae using sine, cosine or tangent of an angle are not asked in general. Questions based on these formulae do not form a part of even MBA entrance tests. The ones that are asked are of low level of difficulty.
- The ones using angles of elevation are the kind of trigonometric questions asked in exams. The level of difficulty does not go beyond this.
Follow all the tips and strategies mentioned above and we are sure they’ll ease your understanding of questions on Trigonometry in Math. Taking sectional test based on trigonometric applications with also contribute significantly into improving your score.
You might like to read our post on time to work upon concepts of ‘Time & Work’ and QA: question types for Bank, SSC and MBA entrances.
Good Luck!
