Q) From the top of a 7m high building, the angle of elevation of the top of a cable tower is 60 and the angle of depression of its foot is 30. Determine the height of the tower. Ans: Let’s draw a diagram with cable tower AB and Building PQ of 7m height. Angle of […]
Q) A straight highway leads to the foot of a tower. A man standing on the top of the 75 m high tower observes two cars at angles of depression of 30° and 60°, which are approaching the foot of the tower. If one car is exactly behind the other on the same side of
Q) Find the value of ‘p’ for which the quadratic equation px (x – 2) + 6 = 0 has two equal roots. Ans: Given quadratic equation is: px (x – 2) + 6 = 0 or we can rewrite it as, px2 – 2p x + 6 = 0 In this equation, we can
Q) Two concentric circle are of radii 5 cm and 3 cm. Find the length of the chord of the larger circle which touches the smaller circle. Ans: Let’s draw a diagram with 2 concentric circles, both having O as centre. Let the radius of two circles be shown as OP = 3 cm of
Q) Prove that sec A (1- sin A)(sec A + tan A) = 1 Ans: Let’s start from LHS LHS = sec A (1- sin A)(sec A + tan A) = = = We know that sin2A + cos2A = 1 or we can say that, 1 – sin2A = cos2A LHS = = 1 ………..
Q) Prove that Ans: Let’s start from LHS LHS = = = We know that sin2A + cos2A = 1 LHS = = =tan A …….. RHS Hence proved!
Prove that: (sin A – 2 sin^3 A)/(2cos^3 A – cos A) = tan A Read More »
Q) Prove that the angle between the two tangents drawn from an external point to a circle is supplementary to the angle subtended by the line segment joining the points of contacts at the centre. Ans: Let’s draw a diagram with a circle of radius r and O as centre. Let the two tangents RP
Q) Prove that √5 is an irrational number. Ans: Let us assume that √5 is a rational number Let √5 = ; where q ≠ 0 and let p, q are co-primes. 5q2 = p2………………. (i) It means p2 is divisible by 5 p is divisible by 5 Hence, we can write that p = 5a,
Q) Which term of the A.P. : 65, 61, 57, 53,………… is the first negative term. Ans: This is A.P. of decreasing order. In the given A.P., we can see that: First term a = 65 and common difference d = -4 Let first negative term be nth term, say Tn We know that nth
Which term of the A.P. : 65, 61, 57, 53,………… is the first negative term. Read More »
Q) How many terms are there in an A.P. whose first and fifth terms are -14 and 2, respectively and the last term is 62. Ans: Let’s consider an A.P with first term as N1 and common difference as ‘d’. Next, we know that nth term of an A.P. = a + (n-1) d