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if 3sin theta + 5 cos theta =5. then find the value of 5 sin theta -3 cos theta.

Rhinithaa PT , 13 Years ago
Grade 11
anser 4 Answers
Tushar Makkar

Last Activity: 13 Years ago

ur ans. is -3

watch  such type of questions are very easy . i solved this ques. in a fraction of sec.

in these questions the best method is to use ur brain if u wanna solve the ques. i watched the ques. and found that 1st equation will be true if cos theta is 1 and sin theta is 0 ... so i put this value in the other equation and hence found the ans.

 

pls. approve the ans, if u liked it

Rhinithaa PT

Last Activity: 13 Years ago

thank u 4 the reply.. but the given ans is 3 and not -3 .....

Ankit Khokhar

Last Activity: 13 Years ago

Sorry for the previous wrong reply, there was a calculation mistake but here is the correct solution.

3 sin x + 5 cos x = 5

so 6 sin x/2 cos x/2 = 5 ( 1 - cos x)

so 6 sin x/2 cos x/2 = 10 sin x/2 sin x/2

so sin x/2 = 0                or           tan x/2 = 3/5

if sin x/2=0 then      5 sin x - 3 cos x = -3

if tan x/2 = 3/5

then sin x = 15/17   and     cos x = 8/17

so  5 sin x - 3 cos x = 3.

Tushar Makkar

Last Activity: 13 Years ago

i am afraid but i have tried the question once more annd the ans. is -3

u can check by putting theta = 0 degrees ... it should satisfy both equation

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