Verified by Ajay Kumar
If x = 7sin A + 24cos A and y = 7cos A − 24sin A, then what is the value of 3(x² + y²)?
1760
2120
1875
1290
Answer: C
On squaring and adding, the cross terms cancel. Thus, \(x^2+y^2=49(\sin^2 A+\cos^2 A)+576(\sin^2 A+\cos^2 A)=49+576=625\). Therefore, \(3(x^2+y^2)=3 \times 625=1875\).
यदि x = 7sin A + 24cos A और y = 7cos A − 24sin A है, तो 3(x² + y²) का मान क्या है?
1760
2120
1875
1290
उत्तर: C
वर्ग करके जोड़ने पर मिश्रित पद कट जाते हैं। अतः \(x^2+y^2=49(\sin^2 A+\cos^2 A)+576(\sin^2 A+\cos^2 A)=49+576=625\)। इसलिए \(3(x^2+y^2)=3 \times 625=1875\)।
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