Prove that: (sin𝒙 − cos𝒙 + 1). (sec𝒙 − tan𝒙) = (sin𝒙 + cos𝒙 − 1) - CBSE Class 10 Sample Paper for 2026 Boards - Maths Basic

part 2 - Question 30 - CBSE Class 10 Sample Paper for 2026 Boards - Maths Basic - Solutions of Sample Papers for Class 10 Boards - Class 10

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Question 30 Prove that : (sin𝒙 βˆ’ cos𝒙 + 1). (sec𝒙 βˆ’ tan𝒙) = (sin𝒙 + cos𝒙 βˆ’ 1)Solving LHS (𝑠𝑖𝑛 π‘₯βˆ’π‘π‘œπ‘  π‘₯+1) Γ— (𝑠𝑒𝑐 π‘₯ βˆ’π‘‘π‘Žπ‘› π‘₯) = (π’”π’Šπ’ π’™βˆ’π’„π’π’” 𝒙+𝟏) Γ— (𝟏/πœπ¨π¬β‘π’™ βˆ’π¬π’π§β‘π’™/πœπ¨π¬β‘π’™ ) = (𝑠𝑖𝑛 π‘₯βˆ’π‘π‘œπ‘  π‘₯+1) Γ— ((1 βˆ’ sin⁑π‘₯)/cos⁑π‘₯ ) = (1+𝑠𝑖𝑛 π‘₯βˆ’π‘π‘œπ‘  π‘₯) Γ— ((1 βˆ’ sin⁑π‘₯)/cos⁑π‘₯ ) = ([1+𝑠𝑖𝑛 π‘₯]βˆ’π‘π‘œπ‘  π‘₯) Γ— ((1 βˆ’ sin⁑π‘₯)/cos⁑π‘₯ ) = (𝟏+𝐬𝐒𝐧⁑𝒙 ) Γ— ((𝟏 βˆ’ π’”π’Šπ’β‘π’™)/𝒄𝒐𝒔⁑𝒙 )βˆ’πœπ¨π¬β‘π’™ Γ—((𝟏 βˆ’ π’”π’Šπ’β‘π’™)/𝒄𝒐𝒔⁑𝒙 ) = ((1 + sin⁑π‘₯ )(1 βˆ’ sin⁑π‘₯))/cos⁑π‘₯ βˆ’(1βˆ’sin⁑π‘₯) = (𝟏 βˆ’ 〖𝐬𝐒𝐧〗^πŸβ‘π’™)/cos⁑π‘₯ βˆ’(1βˆ’sin⁑π‘₯) Putting 1 – sin2 x = cos2 x = γ€–πœπ¨π¬γ€—^πŸβ‘π’™/cos⁑π‘₯ βˆ’(1βˆ’sin⁑π‘₯) = π‘π‘œπ‘  π‘₯βˆ’(1βˆ’sin⁑π‘₯) = π‘π‘œπ‘  π‘₯βˆ’1+sin⁑π‘₯ = (π’”π’Šπ’ 𝒙+𝒄𝒐𝒔 π’™βˆ’πŸ)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 15 years. He provides courses for Maths, Science and Computer Science at Teachoo