IIT JEE , AIEEE Forum - Mathematics , Trignometry - trigonometric equations&inverse trigonometric ratios.

kasirajan.1990

(1)solve:sin3

+cos4

-4sin7

=cos10

+sin17

(

[0,

]).(2)if x=n

/2 and

_sin2_x-3sinx+2

^{(cosx) =1.}find the general solution of x.

gandhamkoushik

1 ans is teta= 180 2 ans is x=n(180)+90

puneet

hiiiii

we at goIIT answer only one query at one time ..

I am also not sure about the (2) question .. i donno wat it means ..

well .. for the fisrt one ..

sin3x + cos4x - 4sin7x = cos10x + sin17x

or, sin3x - sin17x - 4sin7x = cos10x - cos4x

or, -2sin7x.cos10x - 4sin7x = -2sin3x.sin7x

or, sin7x( cos10x - sin7x + 2) = 0

so, either sin7x = 0 or cos10x - sin7x + 2 = 0

if sin7x = 0 .. this means x = 0 ,

/7 , 2

/7 , 3

/7 , 4

/7 , 5

/7 , 6

/7 ,

else if cos10x - sin7x + 2 = 0

this clearly means that sin7x = 1 and cos10x = -1 which is not possible ..