prove that (sin 65°+cos 25° ) (sin 65°-cos 25° ) =0
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Answered by
6
(sin 65° + cos 25°)(sin 65° - cos 25°)
= (0.906 + 0.906)(0.906 - 0.906)
= (1.812)(0)
= 0
Anything multiplied by 0 equals to 0.
= (0.906 + 0.906)(0.906 - 0.906)
= (1.812)(0)
= 0
Anything multiplied by 0 equals to 0.
paakhee:
I am in class 10 we don't have the values of angles except standard angles
see my sol.
its class 10
The question is exactly like the one you asked.
You can type the sine and cosine values into the calculator to get the decimal numbers.
your sol. is correct but this isn't taught in class 10
its higher level
Uh... Well... After you input the values into the calculator, just add and subtract the numbers in the brackets. Then multiply the two numbers and you will get a 0.
we dont get calc. in exams
Oh I see
Answered by
17
(sin 65+cos25)(sin 65-cos25)
according to formula
sin(90-theta)=costheta
now
(sin65+cos25)(sin(90-25)-cos25)
(sin65+cos25)(cos25-cos25) {according to formula}
(sin65+cos65)(0)=0
hence proved
according to formula
sin(90-theta)=costheta
now
(sin65+cos25)(sin(90-25)-cos25)
(sin65+cos25)(cos25-cos25) {according to formula}
(sin65+cos65)(0)=0
hence proved
sinX is = cos(90-K)
where k is the no. when subtracted from 90 gives X
how sin 65 + sin 65 = 0
no cos25-cos25 is zero
in 1st bracket i didnt convert anything
ok
no listen
that was mistake
ok
i corrected it
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