Question

15. Convert

+√

into standard form.



16.Prove that cos 6x + 1 = 32 cos6 x – 48cos4 x + 18cos2 x

( OR )

If sin x + sin y = a and cos x + cos y = b,

then find (i) sin (x + y) (ii) cos (x + y)

17. Prove that sin7x + sin3x + sin x + sin5x = 4sin4x cos x cos2x

( OR )

Prove that 16cos6

0 cos420 cos660 cos780

= 1

18. In a group of 498 students, 142 know Hindi, 171 know Telugu and 49

know Hindi only, 83 know both Hindi & Tamil, 9 know none of the languages,

92 know both Telugu & Tamil and 14 know all 3 languages Find number of

student who know (i) Hindi but not Tamil (ii) Telugu or Tamil, (iii) Tamil only.

please answer please ​

Answer 1

Answer:

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