NCERT Class 11-Math՚S: Exemplar Chapter 3 Trigonometric Functions Part 10 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 6:

Prove that


To prove:

As equation on RHS is a simplified expression, so we must opt Left side equation and simplify it further so that we can get


And thus we will be able to prove it.

By seeing the expression we can think that the problem can be solved using transformation formula:

By transformation formula, we have:

But as LHS expression does not contain ‘2’ in its term. So we multiply and divide the expression by 2.

Applying transformation formula, we have –

Again, applying the transformation formula:


Question 7:



Squaring and adding equation 1 and 2, we get –

Using: , we get –

Question 8:

Find the value of tan .


Question 9:


As we know that-

From T-ratios of multiple angle, we know that