Q. 14.1( 436 Votes )

# Evaluate the following:

(i)

(ii)

(iii)

(iv)

(v)

Answer :

Given is the table of Trigonometrical ratios for different values. Use the values from table for solving the questions.

**(i)** sin60° cos30° + sin30° cos 60°

= 1

**(ii)** 2 tan^{2}45° + cos^{2}30° - sin^{2}60°

= 2 (1)^{2} + (√3/2)^{2} - (√3/2)^{2}

= 2 + 3/4 - 3/4

= 2

**(iii)**

As the denominator has an irrational number, we need to rationalize the fraction

**(iv)**

**(v)**

Rate this question :

If θ = 45°, find the value of

(i)

(ii) cos^{2} θ - sin^{2} θ

Find the numerical value of the following :

sin45°.cos45° – sin^{2}30°.

At a point A, 20 meters above the level of water in a lake, the angle of elevation of a cloud is 30°. The angle of depression of the reflection of the cloud in the lake, at A is 60°. Find the distance of the cloud from A.

Mathematics - Board PapersEvaluate each of the following:

RD Sharma - MathematicsIf , where and are acute angles, find the value of .

RD Sharma - MathematicsEvaluate the following :

cosec^{2}30°.tan^{2}45° – sec^{2}60°